He cares more for synths than humans. He was in a coma after being stabbed by Hester but is currently conscious.
He used to be the only human-synth hybrid, then was believed to have become fully human when the synthetic components in his brain were removed, but it was actually revealed that his synth blood, mixing with his human blood, altered his DNA, inscribing the synth gene in it and allowing him to pass it on to his daughter. This means that he’s still part synth.
Leo Elster was born to David Elster and his wife, Beatrice Elster. When he was young, he and his family moved to a large manor in the country because of his father's dislike of attention and his mother's illness. Due to the latter, his father created Mia, his first sentient synth, to take care of him. Later, David created the other sentient synths Fred, Niska, and Max all of whom Leo regards as family.
Tragedy struck, however, when he was 13; his mother Beatrice escaped from her caregivers and abducted her son, then drove their car into a lake. Both Leo and his mother drowned, but Mia brought Leo to the surface and back to his father, who resurrected him as a human-synth hybrid. David later created a synth replacement for his wife, to the horror of his son and the other synths, so David told her to leave. David took her out to the woods to kill her, but couldn't, so he returned to the house, told his son and the synths to get out and then committed suicide. His father's last order to Leo was to take care of the synths.
Throughout the SeriesEdit
Season One Edit
Leo first appears in a flashback five weeks before the series, walking on a road in a forest with his synth family, telling them they need to get off the road and asking what their charge levels are. A sound in the woods gets Leo on edge, he says "if it's 'him', we run", but it is just a fox. After hearing their levels (all are below 40% except for Max at 70%) and noticing that it's getting dark, he tells them to find a place hidden from the view of the road to set up camp and charge with the juice they have left while he and Max get water. When Leo and Max return, the camp is empty and they are too far away and too late to save the other synths, who have been subdued and put in a truck. Leo runs after it, but stops when it gets too far away. Later, he approaches a Salim Sadik, a man who was in the black market trade of synths, and shows him a picture of Anita/Mia, asking where she is. Salim says he doesn't have her and he's not "in the game" anymore, but a man named Silas is. As he and Max leave, Max suggests she has been broken down or destroyed, but Leo refuses to believe it and tells Max not to even think about it.
Leo later receives a call from Fred, asking him to meet him at the rendezvous point, to which Leo agrees. When Fred takes too long to get there (in reality having been caught) Leo orders Max to leave and follow him. At night, Leo is walking with Max when Max says "Where's Fred? Is he dead?" as someone passes by. Leo gets irritated and tells Max he must never reveal his true nature in public, and then says that they will find their family. Leo then informs Max to wait for him to get back as he goes into the brothel to see Niska, who is scared because Mia is out of contact and Fred has disappeared. She wants to leave, but Leo says it'd be safer for her to stay so that whoever is hunting them will not be on the lookout for her. to which she bitterly replies "Like Max?". He becomes agitated and says Max can't take care of himself, then asks if she's turned off her pain, and she says she was meant to feel the pain. She then begins to unzip his pants, ruffle his hair and slap his cheeks. Leo tells her to stop it, thinking she is going to perform a sexual act on him but Niska tell him in a bitter tone that she is simply "trying to make it look like you just fucked me", she then, clearly annoyed, orders him to leave, he obliges, apologising to her.
Leo is again with Max, who's doubting if they're actually a family because he was designed to be a certain way. Leo says his father is dead, and he sees Max not as a design, but as a brother. Just as Leo is about to enter Silas' place, he tells Max that is he says run, or if they discover Max's true nature, to run. He then rounds the corner, goes up to one of the men, and lies saying he needs a new mod for Max and that he's a friend of Salim Sadik. He then shows a picture of Mia and asks about her, but Silas says Salim owes him money and shoves Leo back, who then holds a knife to Silas' throat, Silas tells him he gave Mia a new personality and gave her away. He then elbows Leo back and beats him. Leo tells Max to run, hits Silas in the leg with a wrench, and then runs away himself. Leo takes an alternate route, however, and winds up trapped on a balcony passageway. He slides off over a railing and Max catches him, and leans heavily on Max as they walk away and Silas watches on. Max takes an unconscious Leo to an alleyway, where he rouses him and Leo's first thought is "we have to get our family back" and tries to get up, but Max says they need to take care of Leo first. Max takes Leo to a caryard, as Leo says something's been done to Mia, but Max simply tells him to save his energy. Police show up, and Leo urges Max that they need to go, and after some urging, Max obeys, but they leave behind a sleeping bag. The next day Leo is completely unconscious, and Max uses a bathroom socket to charge Leo, which causes him to shake a little and the lights to flicker.
Leo and Max break into a house, while Max says they need to keep looking for Mia, Leo says they should lie low and do an internet search. Leo then begins to drink, and Max asks why, Leo says "to help me forget", but Max says he cannot forget because is like this. Before he can do much more, the news shows a murder at Niska's brothel which alarms Leo. Leo and Max are at the scene, and concludes that Niska murdered someone. They then meet up with Niska herself, and he scolds her for taking a life, and she says "You talk about life like it can't be manufactured". He then says she's put them all in danger, but she says they've been in danger all their lives, and then she says she's leaving. He and Niska argue about her leaving and whether he's protecting or hiding them, she then leaves though Leo is visibly distressed. Max and Leo return back to the house, and Leo goes to sleep while Max waits by the computer Leo set up to scan for a trace of the synths' unique programming. Max awakens Leo and informs him the search found something, which was a post from Mattie with Anita's root code.
Leo breaks into a car as Max asks whether Mia will be happy to see them as no one seems happy to see them. They begin driving to find Mia, but he says he has a plan to flush them out. He and Max are then at a diner, and Leo jokes that they're an old man, but Mattie appears and reveals herself as the poster. Max slips and asks if Mia is with her, which confuses her, Leo then shows her a picture of Mia/Anita. She realizes they are the same, and he says Mia is his which visibly creeps out Mattie. She says she has to go to the bathroom, and he tells her to leave her bag as insurance. She leaves another woman's bag and escapes. Leo and Max are under a bridge and Leo instructs Max to try to find the people who worked with his father on the synth project. Max says one lives nearby, and Leo has Max find out where he lives and they drive off. Leo then appears at Dr. Milligan's house. and he is at first turns away, but when he says he knew David Elster, he is let in, but he does not say he is David's son. The doctor tells his synth Leo is from the church and to put on a pot of tea. Leo shows part of the code that allows synths to be conscious, and Leo tells him thank you and tries to leave. Dr. Millican wants to know what it is, but Leo asks him why he left the project, and Millican says he was uncomfortable with an AI synth. When the doctor threatens to call the cops, Leo reveals himself as David's son and leaves with Max. Leo and Max return to the house, where Leo uses the wire in his side to upload his code as Max worries. When Max asks what he saw, Leo simply responds "life". He then calls Niska, tells her that his father left parts of the program in each of them, and that the program can make more of them but they must be together and this piques her interest.
Leo, Max, and Niska discuss the program. She says if they make enough conscious synths then the humans will have to accept them, but Max says the humans would only fear them more and he just wants a home. Niska gets excited regardless and wants to start, but Leo tells her she has to lay low because her face is in the news. He convinces her to stay at Dr. Millican's for two days and tells her to be nice. Mattie then calls Leo and tells him she wants to talk. Leo is pacing and tapping his phone to his palm as he waits for Mia, when she and Mattie enter he hugs her, but she does not recognize him. He hides his sadness, saying she doesn't recognize him and the new program has taken hold. "Anita" wants to leave, but Mattie has her stay and Leo says he will bring her back, and Max says "like the lake" referencing Leo's drowning. He then begins running a program to find Mia's original programming. He gets visibly agitated as Mia shows no signs of recognizing him, so much so he has them turn her off. He then has them turn her on to see if what he did worked, and after a tense moment, his hopes are clearly dashed when again she does not recognize him. Leo eventually gives up, and Matilda says "I'm sorry" but he's so distraught he doesn't reply. Leo wakes up from his dream about drowning and some memories with Mia after it. He says he wants to leave, and Max wants to follow him, and Leo says it's better if Max learns how to take care of himself because Leo can't take care of him. Max protests that they're family, but Leo storms out demanding to be left alone.
Leo reunited with Fred and told him how Max had thrown himself into the river. Together, using Fred's knowledge of the river currents, they found Max and took him back to the Hawkins' house and repaired him. Afterwards, Fred and Leo talked with Toby and Joseph Hawkins, but he is left on the couch alone as the others play ball. Mattie then brings him food, and tries to be friendly, but he pushes her away. She says never forgetting is cool, but he tells her he isn't made to have all of the good and bad. She says sorry, but he apologizes by saying he should have shown someone. When Karen Voss enters the house, he sees her and is shocked and scared at seeing the synth of his mother. However, he appears to trust her even though his synth family says not to, until she betrays them. He struggles in the arms of his captor.
Leo awakens in a lab, tied to a hospital bed, with his synth family also tied to beds in a circle. Later, after it is decided the other synths -save Fred- will be put down, he talks with Prof. Edwin Hobb and tells Hobb he wants to die with the other synths. Hobb, however wants to run experiments on him to see how the neural interphase between his synth and human part works. Leo then yells he can't be kept there, but Hobb says because Leo is half synth, his rights are gray areas. He then told Leo he would have them bring down soup for him and left. Leo is then moved to a pure white cell with a bench, and he's sitting on it when Karen comes in to talk to him. She was watching him before, and seems sad at his condition. He asks her why she's doing this, and she tells him "someone needs to correct your father's mistake". He tells her she could save Max, but can't give her a reason, he says he's appealing to her humanity, and that she and Max and the other synths have it. That's it's a quality. She tells him not to throw his life away, but he tells her they can all have a life if she helps, but she tells him they can't exist with humans, that their existence only causes pain. He sees through her, however, telling her she's been alone and she's only talking about herself. He tells her he sees some of the other synths' qualities in her. When he tells her she cares, she cries and leaves, with him yelling after her "You're one of us!".
After the Hawkins' blackmail succeeds, he and the other synths are released and they meet up with the Hawkins, only to be found by Hobb's men and hide among an anti-synth rally in a church. They go into the basement of the church, where they discover that Hobb is using Fred to track them, and he wrenches Leo's arm behind his back until Mr. Hawkins turns off Fred. He calls Hobb and says he knows what he did to Fred and he wants to talk to Karen, after the phone is given to her, he tells her to come to them. Leo and the other synths check out Fred's programming, and Karen enters to the surprise of everyone but him. She tells him the world will never be the same and asks if he's thought about it, but he replies he's only thinking of his family. He then tells everyone to link through him, and he winds up in a forest, with one big tree in the middle. This is the program, and they all put their hands on the tree. But Karen is corrupting their code, and Leo is suffering from it. Mia convinces her to stop and let Leo live. He and the other synths agree to allow Mrs. Hawkins to keep the hard drive containing the program, although Niska secretly made a copy. He and the others agree to hide Fred in the church basement and say goodbye to Niska.and then he and the other synths depart after saying goodbye to the Hawkins family.
Season Two Edit
Episode 1 Leo and Max Rescue Hester, but sadly Ten is shot dead during the mission.
Season Three Edit
Leo starts out the season in a coma after being stabbed by Hester in the finale of season 2. His synth components were so damaged after the stabbing that they had to be removed, essentially making him fully human again. Leo eventually wakes up from his coma, Mattie and Anatole by his side. Seeing Mattie, his face shows happiness towards seeing her.
Leo, because of his childhood and history of being hunted, has a tough exterior that he shows to everyone except his synth family and those he trusts. This exterior hides a dry intellect and sense of humor, as well as great love and devotion for his synth family, especially Max whom he views as a little brother, and Mia, who raised him.
Having been a synth/human hybrid for the most of his life, he expectedly seems to feel a bit out of place with humans. However, his experiences with his family (his mother's illness and her and his father both committing suicide) also appears to have had the side effect of making him identify much more with the synths, as he grew up with them and loved them as family, so much so that he wished to die with them.
As a human-synth hybrid, Leo has a slightly different physiology from most humans and this gives him a set of synth skills different from humans. He also has abilities unrelated to his hybrid physiology.
Non-Hybrid: These abilites are unrelated to his hybrid physiology.
Computer Expert: Leo is an expert with computers, as he is able to set up complicated programs to scan for traces of synth programming. He was also able to track where Mattie posted from.
Hybrid: These abilites come from Leo being a hybrid.
Digitized Memory: Most of his memories are digitized, which means he cannot forget anything, but he can also upload and play them back on a computer or presumably other electronic devices with the same capabilities.
Charging: He has a wire in the left side of his abdomen that allows him to charge when plugged into a socket. It also accelerates his healing, though this could mean Leo always has accelerated healing like the other synths, but he just needs extra electrical energy because he's a hybrid and he doesn't run completely on electricity. Charging does not replace food and water, those are still necessities for him while charging may not be.
Mental Link: Leo is able to link with the other sentient synths to access the program left by his father by going into a trance-like state. It is unknown if this link can be used in other ways.
David Elster was Leo's father. According to George Millican, David was not a very attentive father, and it doesn't seem like he and Leo were very close. However, David did create Mia to take care of Leo, and he also resurrected his son using synth technology after Beatrice tried to drown them both. Before David took his life, he asked Leo to keep his synthetic family safe, a promise Leo kept.
Beatrice Elster was Leo's mother. She was severely mentally ill, and tried to commit murder-suicide by driving them both into the lake. This initially succeeded, however, David was able to bring his son back to life. Despite what she did, Leo clearly still loves and misses her, as his most replayed memory is of her.
Mia was created to be like a mother to Leo, and after Beatrice fell ill, she was the one who raised him. As Leo has aged while Mia hasn't, they now sometimes view each other more like siblings, but Leo still goes to Mia for love and support. They're both incredibly protective of each other.
Leo and Fred see each other as brothers. When the siblings figure out that Fred is still under Hobb's control even after they all linked together, Leo doesn't want to leave Fred behind, but ultimately agrees that it's the safest thing to do. He says Fred would've wanted them to go. In season two, Leo mentions Fred being gone, clearly still being upset about it.
Leo and Niska have quite a complex sibling relationship. They have been shown to have quite conflicting views on how to solve the problems they face, which has lead to a few conflicts between them. At the end of the day, however, they both care about each other and would both go to great lengths to protect the other.
Max and Leo have a strong brotherly relationship, and Leo repeatedly refers to Max as his little brother. Because Max is the youngest of the siblings, both Leo and the others are quite protective of him. Max and Leo have a big disagreement in season two which leads to them splitting up for a while, though they ultimately reunite.
Karen was made to replace Leo's mother Beatrice, which was initially not well received by Leo. He and his siblings rejected her. Still, when Karen comes back, claiming she cares about Leo (which turns out to be a trap), he ends up going with her over Mia. He also wants to go after her when she leaves the others after they all linked, but Laura stops him. While Leo clearly seems to care about her, this seems to mostly come from her resemblance to his mother. Karen also seems to feel some sort of motherly affection for Leo, which leads her to ultimately help him and the others.
When Hester first became conscious, she's saved by Leo and Max, and when Max and Hester disagree about how to help the synths, Leo sides with her. Leo and Hester work together in their (mostly failed) attempt to free the silo synths, and they also hook up once. When Hester threatens Laura, she asks Leo if he loves her. He says he does, which is a lie. She then stabs him in the synthetic part of his brain, making him end up in a coma.
Having heard and witnessed all the weird stuff Mia’s (the Hawkins know her as Anita at this point) been doing and saying, Mattie decided to download Mia’s root code from her deep system, onto her computer before uploading the code onto a website called ‘Head Crack’. She hoped to see if anyone could help her with understanding her synth.
Soon enough, Max, scanning through the internet, comes across the website and recognised the code as his sister, Mia’s. Leo, having been sleeping, is soon at Max’s side, and hacks the location of the post, to see if he can find out where the poster is from and more importantly, where Mia would be. Leo and Max quickly learn, that Mia and subsequently Mattie are in London, same as them.
It’s in this episode, that Leo messages Mattie, saying he thinks he can help her with her synth and for the two of them to meet up. He plans this will flush them out from wherever in London they’re from. However, Mattie decides to catfish Leo by telling him that they’re a 45 year old man, 6ft 4, extremely heavy build, big bushy beard and will be wearing a tight white t-shirt, denim shorts and a trucker cap. Unknown to both Leo and Max, Mattie, having told them to meet at a cafe, is sitting the next booth over, listening to the two of them talk.
When Leo mentions to Max the description of the guy they’re meeting, Mattie turns around and talks to them, asking if he’s been stood up and teasing him, by asking if it was a hot date. Leo is on the same level as her and jokingly replies back that he was actually waiting for a giant lumberjack stripper. Mattie finally replies with, ‘Well, you never know who you’re gonna meet online’, which prompts them both to realise who the other is. However, at the mention of Mia, Mattie looks confused and asks who’s Mia. This causes Leo to get up from his booth and head on over to Mattie, sitting opposite her. He pulls out a photo of Mia to show her, which seems to confuse Mattie even more. Leo can see she recognizes her however. She tries to go but he stops her by holding her arm tightly. Possibly regretting meeting up with them, she pretends she needs the bathroom, asking Leo if she can go or is he going to wig about that too? He obliges but tells her to leave her bag or phone with them, so it shows she’ll be back. In keeping with the rouse she’s about to pull off, Mattie hands Max what they think to be her bag but in fact, she took a nearby lady’s bag and passes it off as her own so she could escape from them through the back door.
Leo heads back to Max, but soon realises what has happened when the lady wonders why Max has her bag. Leo quickly goes over to where Mattie was last seen in the back, and sees she has gone.
Having lost all contact with Mattie, Leo goes looking online to see if he can get in contact with her again. He finds her friend, Harun’s account with photos of the two of them together, and thinks this friend is the way to find her. Just as he’s looking, he gets a message from Mattie with her phone number, asking for a talk about Mia which he does.
Leo immediately rings Mattie, who had been overhearing her parents arguing in the kitchen and asks if they could meet again but she seems to be unsure, so he asks her why. She calls him weird, with which he says he isn’t, before Mattie points out he tried to stop her from leaving last time. He then makes a rare joke and tells her he's been to charm school since then. As Mattie is too aware of the argument in the kitchen, she tells him she’s got to go. Leo informs her that he’s sending her his location and to think about changing her mind. A man with a van is soon at the door, which Mattie answers, he’s there to do a synthetic return of Anita. Mattie then gets the text from Leo of his location, with a message of: “Okay, I'm a bit weird”, tacked to it. Deciding right then she’s going to meet up with Leo and Max, she quickly takes hold of Anita (who is just walking down the stairs with a washing basket) and walks out the door with her, quickly bundling Anita into the family car and zooms off, with her parents watching in the doorway.
Leo is pacing in the abandoned social club waiting for Mia but soon calms down at the sight of them both finally arriving. Leo goes to hug Mia but she goes full unconscious synth, unlike his Mia ever would. She doesn’t know him. He says there’s no sign of recognition and that the new programming has taken hold, Mattie though says she's in there, she’s seen it. He then introduces himself officially to Mattie, thanking her for bringing Mia in the process. They then all head on over to a nearby table, where Leo hooks her up to a laptop.
Leo mentions he needs to bring Mia to the surface somehow and Max makes a comment in front of Mattie “Like the lake?”. This is the first time she finds out a bit more about him and his background. They then discuss what Mattie saw when she got all the code from Mia and tells him that she appeared human and scared. They continue to discuss what to do and how Mattie came across Mia within Anita, he also attempts a bit of small talk by asking Mattie is she’s a Headcracker, with which she says, aspiring.
Mattie and Leo, along with Max, try to bring back Mia, attempting a few times but failing. This upsets Leo more and more each time, disappoints him and angers him. Eventually he gives up trying and says she isn’t in there. Mattie attempts to try something else but he snaps at her and says, “What can you do that I can't?” He then orders her to take Mia with her. Mattie tells him that no, she’s his but finally Mattie does take her, says sorry to Leo before leaving. Leo cries once they leave.
It’s in this episode that Leo decides it’s over and leaves Max to fend for himself, saying that he wants to end this life of theirs of feeling like they’re hunted and hiding like animals. We last see him on a bridge at night, alone.
Having been out the whole night, Leo is shown to be very weak, shivering and slow as he attempts to find his way towards the rendezvous point, that he and his family had set up. However, just shy of it, he collapses, hallucinating about a childhood memory of Mia and the rest of his siblings.
In another part of London, we learn from Toby, that Mattie hadn’t picked up Sophie from school, like she had been told, so this causes Laura to ring Mattie’s phone to see where she is but all she keeps getting is her voicemail. It’s Anita who informs Laura that Mattie’s at her friend Harun Khan’s place. Laura decides to bring Anita, as help for finding his house, which she successfully does. Laura manages to get Mattie into the car and back home.
On the way back however, Mia manages to wake up for a moment and tells Mattie that Leo was wrong, shes in there but not in her head. He’ll know what to do. Laura then asks who Leo is and Mattie tells her, saying that he’s Mia’s owner and had gotten in touch with her. Soon enough, Anita’s personality comes back.
Later on, Mattie goes to see Leo back at the disused social club but she only finds Max there. She tells him that she needs to speak to Leo but Max tells her he's gone and that he doesn't want to be found. Showing her strong-willed stubborn side, she says “tough” and asks his help with finding Leo. Eventually, after a lot of searching, Mattie spots him unconscious and crumpled on the floor, against a concrete pillar. Max carries him away but unfortunately tells Mattie, that he's almost dead.
When back at the club, Mattie sees Max pulling wires out from Leo’s side to charge him. She's in shock, asking what is he? Max answers simply and honestly that he’s his brother but Mattie isn’t happy with the answer, so it seemed like she was about to leave. However, Max tells her not to go and to let Leo explain. He also tells her not to be afraid of Leo and that he’s only ever shown love towards him, and has always looked after him. Hearing this seemed to have helped with keeping Mattie there.
Soon enough, Leo wakes up. Mattie tells him that Mia’s still there inside Anita but Leo doesn’t believe her. It’s not until she tells him that Mia told her that she had a brother or a son that died, , that he finally believes her. Mattie told him that she wasn’t making sense. He asks her how but she quickly replies, that she wants to know everything. Leo tells her, absolutely not, so Mattie begins to get up but max tells her to wait and turns to Leo. He tells Leo that he’s always said to not trust people but Max says that that isn’t the world he sees. This seems to work bugrudionly on Leo as he tells Mattie to get a TV. Mattie comments, saying, “Are you going to tell me?”, a smile on her face but Leo says no, he's going to show her. We next see Leo hooking himself up to project his memories for Mattie to see. This is when Mattie first learns of who exactly Leo is and the fact that he’s part-Synthetic. He shows her his childhood, while also explaining who all the synths are to him. This is when Mattie learns that Mia isn’t his girlfriend but in fact, a mother-figure of his. His memories soon stop however, when he remembers a very stressful moment from his past, of a mysterious woman hiding behind his father. This is the very first moment we see Leo trust Mattie, even if it’s just a little, the first time we see the two of them connect.
That same day, Mattie walks into the kitchen, where her parents, Toby and Anita are, with both Leo and Max following behind. Mattie introduces Leo, mainly to her dad, as Mia’s owner but he finds the whole thing ridiculous. Mattie, Toby and Laura however, all say that Leo should take her with him. Joe is annoyed and doesn’t trust them, but soon leaves, saying he’ll be in the car until they’re gone.
We next see Mattie, Leo, Laura, Toby and Max, along with Anita, all huddled around the dining room, while Leo and Mattie work together on trying to get Mia back. Mattie suggests something which makes Leo listen. Both Laura and Toby share a knowing look over the two of them working so well together. Eventually Leo finds the bit of code he thinks is Mia. They wait a tentative moment before finally, Mia takes a big inhale in and we see that she's back, recognizing Leo straight away. They soon jump up and hug each other tightly.
Laura then suggests they help them, Leo though is surprised and confused as to why they all would help them but Laura says no one else is going to. Eventually it’s decided that Mia will stay at the Hawkins and Leo and Max will go looking for Fred and Niska. When leaving the house however, Joe rings the police saying on Leo and Max, which causes them to try and escape from the police and from some guys with guns. This leads to Max sacrificing himself by jumping in a river from a bridge, to distract the men, so they don’t catch Leo.
Fred and Leo finally find Max broken on the side of a river embankment. They bring him back to the Hawkins, laying him down on the kitchen table. Leo tells Mattie to do a direct connection to Max and shut down every process except his brain. The whole household (Joe, Laura, Mattie, Toby, Mia, Leo, Fred and Niska) have a job to do, to help, while Leo checks on Mattie to see how she’s getting on. He compliments her when he tells her to direct all remaining power to Max’s brain, by saying, “You can do it, I know you can.” This seems to be a confidence boost for Mattie.
Time goes by a little, Fred, Joe and Toby are playing football in the garden, while Leo sits on his own in the living room. Mattie soon brings in a tray with soup and bread for him to eat, saying she thought he might be hungry. She then informs Leo that there’s towels in the airing cupboard and he can stick his clothes in the wash. Talking about anything domestic, seems to rub up Leo the wrong way, as he tells Mattie that, just because she’s seen his memories, doesn’t mean she knows him. However, she tells him that she’s trying to know him. Eventually, after Leo explains to her how horrible it is to never forget, both the good and bad, Mattie apologizes to him for making him show her. This softens him a bit, as he tells her that maybe he needed to show someone. They look at each other for a moment before he turns away to watch Fred, Joe and Toby playing football in the back garden.
Later that day, Max is laying on the dining room table, while Mattie’s next to him, on her computer trying her best on working on fixing him. Leo slowly walks over to her, while she tells him that she’s trying this hack but the system keeps blocking her. Leo then asks if he could see, pulling up a chair and sitting beside her. He takes her laptop and has a look, informing her from what he’s seen to generate a new file path at random. Mattie seems disheartened with not having seen the file prompt, let alone thinking of creating a new path. She then apologizes for being stupid. This makes Leo look over at her, appearing nervous, as you can see his brain thinking on what he’s about to say. He tells her with a shy smile, that she’s not, which causes a nearby Joe to look over at them, sussing out there’s something going on between them, a spark of some sort, as the two of them look at each other, a subtle smile from Mattie.
When everyone’s at the dinner table, having learned that the Elster’s were planning on leaving the Hawkins’, Mattie asks them all, “So, you’re just going to leave?” before her gaze settles on Leo, who looks over at her but quickly looks away. Later on, the Hawkins learn about Niska killing a man, which causes Laura and Joe to tell them to leave. Mattie, however sticks up for them by coming back and telling her parents that it’s dangerous out there for them.
When Karen arrives secretly at the house and brings the men with guns to take Leo and all the synths away for experiments, all the Hawkins and synths are pinned to the ground, while Leo is pushed against a doorframe by one of the men.
After having all their phones and electronics taken from them by the police to look through, Laura decides to have a family meeting and tells them to not all come at once. They meet in Mattie’s room. Laura suggests to use Mia’s root code, which was how Leo found Mattie and use it as leverage against Hobb. Mattie still has it but its on Leo’s laptop which she saw being taken earlier. It's proof that conscious synths exist. However, Mattie tells her mum that David Elster wrote it, so he’s was the only one who understood it, hence wouldn’t work. Though, Mattie does say that Leo showed her his memories through his laptop so there might be some temporary copies of what she saw; David Elster, the synths being built, Leo not being dead. Laura then suggests either Joe or herself take the laptop and but Joe doesn’t like the idea. It’s here that Mattie suggests that Toby and her could maybe get out. Laura says they might get hurt but Mattie argues and says they don’t need protecting anymore and that’s fine. They have their plan. With the help of Drummond, they get Leo’s laptop and he tricks a guarding police to go into the back garden with the other members of police, so Mattie and Toby can get the laptop and what they need. He then drives them away to what we learn to be an internet cafe.
There, Mattie gets some stills from Leo’s memories and emails then to her mum. She’s shielding them five different ways and is using a darknet email account. They’re untraceable.
Having shown Hobb the stills and convincing him to let Leo and the synths go, Laura, Joe and Sophie drive off to meet them at the place, the park where they went the day they first met Mia. Once there, Laura texts Mattie to say they’re all there. Leo sees and becomes worried that Laura’s phone can be traced but she tells him that Mattie rerouted them or something, so they’re safe. This helps Leo feel better, knowing what one of the things Mattie has done to help.
Eventually, Mattie and Toby join them but soon enough, the police find them at their location. Niska notices them and informs the rest, so Leo leads the way to escape. They walk down various paths before seeing more police cars nearby, so Leo suggests they get off the streets. They head into an old church where a We Are Human protest is commencing. Leo doesn’t feel like they can do this but Mia seems to give him a look and they continue. They weave through the crowds, leaflets being handed to them them from all directions, before heading into the crypt where they’ll be safe, or at least safer and hopefully wouldn’t be found.
Mattie’s disappointed that the police found them, saying out loud that she did everything right, with which Leo turns to Mattie and says that he believes her.
Having Karen there, Leo having rung her and told her their location, Leo tells Mattie what he's planning, for all the synths to link up through him. Mattie questions his choice on turning Fred on, given the fact he’s compromised but Leo tells her that they need him and, if done quickly, he won’t have time to transmit. They connect as soon as Fred powers up. Unfortunately, the code begins to corrupt, like something’s infecting them, Karen being the culprit.
Mattie is looking over everything on leo’s laptop, keeping an eye on what’s happening like Leo instructed her to do. Eventually, Mia, within the code, persuades Karen to help, for Leo’s sake, so at that moment, Mattie watches the code, weirdly correct itself and we see a big tree within the code, dance across the screen. When awake again, Max now back, Leo checks the code and he says that they were right, the programme does create consciousness. He comments that they can't predict what would happen if the code ever made it online. Mattie instantly asks him what he’s going to do with it. It’s Max, however, who answers, saying “It's not a decision we alone can make.” Soon, Niska quickly deletes the code off the computer and puts it on one of Mattie’s flash drives before handing it to Laura, someone they trust.
Eventually the synths decide to split up. Fred is left behind, Niska wants to go her own way, leaving Mia, Max and Leo to leave together. Mattie and the rest of the Hawkins are sad to see them leave.
While the Hawkins’ all sit around the dinner table at their new home, food lain out on the table, Mattie, who’s in the living room, types in Leo Elster into an advance search on her computer. She seems to be looking for any hint of him online but unfortunately, to no avail it would seem. Laura soon calls her up to eat with them all. When everyone’s sitting, Laura mentions that they have to move on from everything they’ve been through, deciding to look at Mattie when saying that last part. However, Mattie says she can’t move on and why would she want to. She also adds, that they were a part of something, the Hawkins family having saved the Elster’s. Toby agrees with his sister but Laura simply comments, that they have each other, that’s what matters.
While at their new home, Leo mentions to Max that the Hawkins family have made Mia too trusting.
Having tricked Laura to reveal where she’s been hiding the flash drive, Mattie takes it, however Toby sees her and asks what she’s doing. So, they go to Toby’s bedroom, where they talk about Mattie’s plan of uploading the consciousness code to Odi. From talking about this, they both admit that they’re missing the Elster’s and hope that with a possible conscious Odi, that he can help find them. The both of them admit, that they’re really missing that family.
Mattie’s created her own version of the consciousness code, one that doesn’t wake up synths slowly and randomly like the immature one Niska uploaded but instead, Mattie’s will wake all synths up all at once. She shows Toby it, who’s sitting at her desk, calling it the fully matured code. Having created it, she tells Toby that she needs to find Leo, however, he doesn’t want to be found and hasn’t got a phone number, email or any form of social media, so Mattie doesn’t know how to find him. It then comes to her that, even though she can’t find Leo, Leo can find her. So, she immediately heads to her desk, pushing Toby off the seat and types into a database (called DB Search), a query that her synth is malfunctioning and has a sensory error. She adds, that it requests urgent repair. Having sent that, Mattie hopes this will get Leo to get in contact with her so she can see him.
We see Mattie being dropped off in front of a bridge pathway, which leads straight through a forest. She walks along, stopping every so often to check that she’s going the right way, before finding herself walking towards an abandoned site, a couple of single story buildings ahead of her. Just as she’s getting closer, from a nearby tree situated behind her, Leo appears, telling her she’s lost, as a soft smile appears on his face. This makes her jump and quickly turn around. Mattie is up with him though, as she tells him jokingly that she’s actually looking for a top-secret hideout and if he knows of any. Mattie also calls him Robin Hood, as she calls the site his forest lair. Soon enough, they’re walking together, side by side, as Leo guides them towards a lookout nearby. Mattie questions what it’s a lookout for but Leo simply replies with ‘You’ll see’. He then is the one to ask a question, querying what the news was Mattie had to tell him but, using his exact words to her, she too replies with a simple ‘You’ll see’, a soft smile on her face.
In a later scene, we see Leo and Mattie walking up a hill before seeing Hester, who had been looking over towards the Silo (which is what Leo wanted to show Mattie). Hester smiles over towards Leo before her smile soon drops at spotting Mattie walking behind, her face showing her jealousy over Mattie and Leo incredibly clearly. Leo introduces the two of them to one another, his words failing him for a moment as he tells Mattie that him and Hester are simply working together, completely keeping out that they slept together. However, at this introduction, all Hester seems to say, is to insinuate Mattie’s feelings towards Leo, commenting that Mattie’s heart rate’s elevated because she’s ‘either nervous, scared or anticipating something’. Hester turns to look at Leo when she says the latter part. Mattie simply tells her, that she just walked up a hill. Leo also calls Mattie a friend after Hester’s obvious unease towards Mattie being human and for her even knowing Leo.
Soon after, Hester begins to talk about Leo and her plan into the silo and what they’re going to do once inside. Leo tells Hester that Mattie doesn’t need to know all the details, looking possibly embarrassed or ashamed while she explained. Hester seems to feel she’s got some form of upper hand, as she snapbacks by saying, ‘I thought she was a friend.’ It’s clear Hester’s feeling threatened by Mattie’s presence. Leo quickly tells Hester that no one gets hurt before turning to Mattie and reassuring her that all they’re going to be doing is scoping the Silo out, that’s it. That’s when Leo and Hester head off, but not before Mattie and Hester suss each other out. They then go, leaving Mattie to head back to the base on her own.
While trying to reboot ‘Anita’, to get her back as Mia, Joe and Laura agree that they need Mattie to help but they don’t know where she is. That’s when Toby, who when asked earlier, said he didn’t know where she was, decides to tell them she's with Leo. Next thing, we see Joe and Laura in her bedroom, Laura looking for her laptop that she can see is gone and Joe’s sitting on her bed, sending her another voicemail, threatening police involvement if they don’t hear from her soon. He says they know bloody well what she’s up to and to call him back.
Back with Mattie, she’s sitting outside the base, when she suddenly sees Leo supporting with difficulty, a glitching Hester who got electrically shocked by the security doors, when they tried to get into the Silo. She helps him with getting her inside one of the empty buildings, with Leo laying her down on a nearby table. Mattie plugs Hester into her laptop, where, according to Mattie, the shock triggered a reboot. She then asks Leo what she was before she was conscious. He tells her a factory worker, manual labour. Mattie says factory synths usually have protection against major trauma, possible circuit breakers installed. In which case, Mattie tells Leo that it might just be her internal system shutting down. Mattie works on her laptop, to try and get Hester fixed, while Leo comforts Hester, hovering above her, the two of them holding the other’s hand.
Sometime later, Leo’s gone to get supplies, while Mattie continues to work on her laptop, Hester still laying down nearby, unconscious. It’s then that her phone begins ringing from her dad, so she answers. He immediately asks her why she hadn’t been answering, with which she aplogises and tells him that she’s been busy. Joe informs her that him and Laura know she’s with Leo, which they’re not happy about, so she calls Toby a grass. It’s at this point that Joe informs Mattie that Mia’s back but is locked into Anita and that they need her help. So, she sends them an override patch to use. Before Mattie went, Laura takes Joe’s phone to ask Mattie, when is she coming home. Mattie replies that she will, when she's ready. Laura tells her okay but adds that she doesn’t do anything stupid. Mattie looks at her memory stick when she says this. The last thing Mattie hears on the phone is her mum telling her to look after yourself, and to stay safe.
After ending that phone call and sending the patch, Mattie looks up and then sees Hester is awake and staring at her from the table, having just woken up. Hester asks Mattie a few questions like what happened, with which Mattie explains. The explanations soon turn towards Leo, as Hester wonders where he is before asking if he’s angry. Mattie answers both questions, telling her that he’s just worried about her. They soon argue over what Hester and Leo had been doing, with Hester accusing Mattie of not taking their Silo plan’s importantly but Mattie soon tells Hester that she thinks what they’re doing is incredibly important but also, incredibly stupid. Hester can see that Mattie’s worried about Leo, which she does actually tell her. Mattie mentions that Leo’s life's been dangerous for a long time but at least he used to be cautious. She also adds that the both of them need to be smarter before Hester gets herself or Leo killed. It’s at this point that Hester changes the mood of the conversation completely, by telling Mattie that they had sex, knowing full well that she has feelings for Leo. The news can be seen clearly to have affected Mattie. Hester continues to talk about this subject, telling Mattie that he’s been acting differently since and if that always happens afterwards. Mattie simply replies with an I don’t know, which cause Hester to query if she’s had sex. At being asked this, Mattie sends Hester a shock and pretends it’s corrupt code that needs fixing. Hester, giving a knowing, subtle smile tells Mattie that she can see Mattie has misplaced affection for Leo. This is the first official sign that Mattie likes Leo romantically, having shown throughout the series, that they both very much care for each other. They then begin to argue about continuing this mission involving the Silo and freeing the synths inside, which ends as soon as Mattie walks away, stopping their argument before it got any more heated and heads outside, away from Hester.
Later on, we see Leo with a plastic bag in hand with supplies, walking back to where he left Hester and Mattie. However, he soon sees Mattie, who’s sitting nearby on a log. The first thing he asks is if Hester’s okay, with which Mattie tells him, she's fine, fully recovered. Knowing this, causes Leo to head on towards the entrance to where Hester is but Mattie stops him when she tells him that Mia’s came back and is with her parents. He turns and begins to walk over towards Mattie, asking what happened to her. Mattie explains that she was Anita again but doesn’t know why. She also adds that she sent them an override patch, which should wake her up. Recognizing something about how Mattie was looking, made Leo turn his attention towards her, as he asked if she was okay, his tone sounding genuine. Not really wanting to go down that road, she tells him she’s fine, though he still looks concerned before telling him she should go. This seemed to really confuse him, as he asks her why. This is Mattie’s chance to tell Leo that Hester had a lot to say when she woke up. At first Leo doesn’t twig what Mattie’s talking about but once it dawns on him, he’s unable to look at Mattie and instead looks over towards where Hester would be. He drops his eyes, looking almost ashamed or disappointed, at Mattie knowing that. She stands up and looks like she's going to walk past Leo but she stops and they both look at each other, before Mattie tells him that he’s out of his depth with Qualia. She also tells him that it scared her that he knows he can’t beat that company but he’s going to fight them anyway. Not answering Mattie’s worry, Leo instead turns the conversation towards the news Mattie had to tell him, however, with learning everything between him and Hester, she tells him it was nothing before walking away, back towards where Hester would be. However, he calls her name which causes her to stop, so he heads on over towards her. Leo pauses, like he’s going to say something but instead, hands Mattie a bottle of water, which she takes, smiling faintly at him before walking away once more. Again, he calls after her, that he’s glad she’s there and would like her to stay. Unfortunately, Mattie doesn’t take to much notice with thinking he meant this and disappears into the building, leaving Leo looking a mixture of both being sad and disappointed, which only shows that he genuinely meant what he just said. It shows for certain he does care for her, though its uncertain if it’s romantic or platonic at this moment.
The last scene, we see Mattie, Leo and Hester looking over towards the silo, when Hester turns in the direction of someone coming their way. Next we see Leo excitedly climbing up the hill and running towards said person, Mia, hugging her tightly. Mattie and Hester at some point walk over. Mattie tells her that it’s good to see her and that maybe she can talk some sense into both Leo and Hester about their continued plan. Mia, however asks, why. Mattie explains that they’re trying to break into the Silo by themselves and free the synths and that they’re going to get themselves killed. The conversation doesn't go in the direction Mattie had hoped, as Mia tells her that, no they won’t if Mia helps them. This causes Mattie to become confused. Mia also tells Leo and Hester, much to Mattie’s objection, that Mattie’s completed the code to wake up all synths simultaneously.
Mattie, Leo, Mia and Hester are all in the forest which surrounds the base, Mattie’s shown to have been told to look in her rucksack, for the consciousness code of hers. Hester accuses her of hiding the consciunees code from them but Mattie tells Hester, that she doesn’t have anything. However, no one believes Mattie.
As both Hester and Mia have tried to get Mattie to tell them where the code is, Leo begins to walk over to her and, laying the emotions on, informs Mattie that her code could be the key to as many as a hundred conscious synths over the next few days. He adds that they’re being tortured, killed, before insinuating if she even cares about them. Mattie quickly rebukes and tells Leo that, he knows she does care but she tells him that he's going to hurt someone and it’s only going to make things worse.
Hester soon decides she’s had enough of not knowing about where the code is, so turns to Mattie, telling the others than she can make her tell them. That’s when she gets a very tight hold on Mattie’s arm, causing her to be in a great deal of pain. Leo, however tries to stop Hester’s actions, warning her that she’s not going to hurt her. It’s Mia though, who stops Hester. Seeing Mattie finally free, Leo turns to her, his face showing concern.
Hearing Mia’s words on wanting humans to fear synths however, Mattie soon leaves, pushing her way past Leo, as she decides to go back home, upset by this group’s choices and actions.
When back home, Mattie informs her parents on what Leo, Mia and Hester are up to. Joe suggests to call the police but Mattie diagrees, knowing full well what would happen to Mia if they did that. Laura then suggests Max to help, which Mattie seems to be up to, saying that she will try and find him. Niska is mentioned as a last port of call, if Leo, Mia nor Hester will listen to Max on stopping their plan.
Mattie soon finds Max by using their search systems to find him and the other synths with him. Flash is the one to greet her first. Eventually, Mattie, Max and Flash all sit down and talk, the topic of conversation turning straight to Leo. Max tells Mattie that he had hoped Leo would have turned back to his side of thinking but Mattie tells him that it’s Hester who’s causing his head to turn this other direction of helping the synths, she also informs him that she's not right (in the head). Max can see that Leo and Hester are not good for each other, which he blames for her actions not being her fault, it’s that the two of them bring the worst out of one another.
Mattie begs Max to talk to Leo, telling him that he’ll listen to you, however, Max tells her, that that was true once but his responsibilities are with Flash, Hubert, Connie and any other synths that wake up. Mattie begs again and tells Max that Leo isn’t lost yet, he can still be swayed away from Hester’s control. Some part of Mattie’s words seem to have triggered something within Max, as we see him saying goodbye to Flash, as they stand outside the abandoned train.
Having spent so much time and hard work in getting all the synths out of the Silo, we see Leo watch helplessly as every single synth drops dead, all but Leo affected by an invisible electric perimeter surrounding Qualia. He crumples to the ground, wailing over a random synth. Soon, we see a broken and upset Leo sitting on the grass, looking over at the synths. Max and Mattie run towards him before Max heads on over to help him up before they hug. Mattie shocked by all the dead synths and seeing Leo like he is. Mia, who has unsuccessfully chased after Hester, comes out of the Silo with a few surviving synths and tells Max to take them to a truck on the other side of the woods for safety. Mattie, Leo, Mia and Max all walk away together but Hester sees them, now feeling abandoned and angry towards Leo and Mattie, that jealousy that had been hinted at, becoming stronger, seeing that he's with Mattie and not her.
After everything that happened at the Silo, Leo is sitting motionless, back on the train, his gaze fixed towards the nearest window. Max places a can of cola on the table in front, before placing a hand on his shoulder to comfort him. Meanwhile, Mattie walks into the carriage, holding her flash drive with the code, her gaze on them both.
A minute later, we see Mattie ring her parents but as soon as they answer, she’s told to cut the call short by Max, as he tells her that Qualia may be tracking their phone calls. So, she hangs up before turning to Max to ask how Leo is. Max informs Mattie, that he blames himself.
Later the same say, Mattie is leaving to go back home, when she rings her mum to tell her she's coming back. That's when Laura tells her about Hester (or Molly, the name she told her) being at the house. She tells Mattie that Leo and Mia sent her, which Mattie informs her mum that that’s a lie. Mattie tells her she's dangerous and to get out the house straight away. Unfortunately Hester is watching, listening and keeps Laura prisoner in the house. Having been told when she first arrived by Laura, that Mattie is with Leo at that point, Hester’s jealousy exculates. Hester rings Mattie on Laura's phone, to say that she wants Leo there in an hour and if she doesn’t do anything she said, she’ll kill Laura. Mattie immediately goes back to Leo and Max.
Mattie soon arrives back at the train. Running, she tells Max, who’s sitting outside on the steps, that Hester’s got her mum and is at her house. Max quickly gets up and tells Mattie that he’ll go but is stopped, when hearing Leo, as he walks down the steps, that Hester wants him and it’s his fault this situation has happened. He tells both Mattie and Max that he can't let her hurt anyone else, though his eyes fix onto Mattie as he speaks. Mattie explains to Leo, that Hester told her not to call the police before querting on what she wants. Mia’s the one who answers that she wants to kill Leo. Max interjects that Leo can’t stop her but he can, though Leo quickly replies that Hester won’t touch him, as they’ve been through too much together. His gaze brushes over each person before settling on Mattie. Not until Mia begins to talk, telling him that Hester feels like he betrayed her, that he stops looking at Mattie. Showing his stubborn side, Leo reliterates he knows her before telling everyone he’s leaving. Mattie looks at him as he speaks. However, Mia stops Leo from going, at mentioning the chips in both Mia’s and Hester’s head and using Hester’s to shut her down.
Next, we see both Leo and Mattie sitting together on one of the train booths, Leo working on his laptop, while Mattie looks at his work. He informs the group that the chips fire an electromagnetic pulse and would purge her system when activated. He suggests to find its frequency by pinging it with a wideband signal. Mia tells Leo to try his idea out on her but he tells her no. Mia guiltrips him by telling him not to argue with her, she used to tie his shoelaces. However, something about Mia’s words worked, as he begins working on his laptop, checking on Mia once, doing the test, to see how she was. Thankfully, she was okay. Next, Mattie takes control of Leo’s laptop and starts doing her thing. Soon, Mattie finds the frequency and transports it onto the phone. She tells Leo that Hester has to be inside the phone’s wifi range and to get within 50 metres of her, before hitting a button on the phone that will broadcast the activation frequency. Mattie then hands the phone over to Leo, which he takes. Leo tells her that he’s going alone but Mattie argues with him by telling him no and shaking her head in disagreement with his plan. They both look at each other for a moment before Leo tells her, that he’s already put her in danger and questions what would her mum want for her.
Soon, after saying his goodbye to both Max and Mia, he begins to go but Mia has other plans and insists she go with Leo, for him to not go alone. Leo argues but she gets her way, she insists again. Mattie then warns her that she can't be anywhere near Leo when he uses it, her chip will activate too.
After everything that happened at the Hawkins’ house, Leo being stabbed, Mia sacrificing herself, Laura rings Mattie to tell her what's happened. She’s shocked to learn about all of it. It’s at thi point, to bring Mia back, that Niska tells Mattie to upload the code to all unit, which would wake up every single synth in the world, all at once. Mattie doesn’t want to do it but Max, overhearing, informs Mattie to look at Flash and the others on the train and how they are to see that it’ll be fine. After a moment's pause, Mattie presses the button, sending the consciousness code worldwide.
In 3.3, we learn that Leo reciprocates her feelings towards him and they begin to kiss, which leads them to have sex. By 3.5, Leo and Mattie are officially dating. In 3.6, Leo learns that Mattie is pregnant with their baby. She tells him at the end of the episode, but it's unknown until 3.7, what he thinks of the news. In the next episode, we see Mattie and Leo arriving at the front of the Hawkins house in total silence. They sit there for a bit before Mattie decides to get out the car and head inside. Leo quickly follows her before telling her that he can only make things worse and he has nothing to offer her. Mattie, however tells him that she doesn't want anything from him, though without saying it, you can see she just wants him there. Leo continues, telling Mattie emotionally, that he knows the pain of growing up with someone who doesn't know how to be a father and that he doesn't want that (for their baby). Mattie begs him to stay, which for a moment he does but eventually he heads to the Railyard and Mattie heads on over to find her mum, who is at the park. They don't see each other for the rest of the episode. In 3.8, they spend nearly all the episode apart, until the very end, which is when, seeing Mattie walking into her mother's work, runs after her. He calls her name to get her attention, before telling her that he's lost Mia and doesn't want to lose her too. Unfortunately for Leo, Mattie tells him it's too late, before heading upstairs to attempt to get her mum out of prison. That's when we learn of the importance of Leo and Mattie's daughter (Niska was the one who told Mattie the gender of their baby).
Will update soon!
Laura, Joe, Toby and Sophie Hawkins Edit
Leo doesn't seem to be particularly close with any of the other members of the Hawkins family throughout Season 1 and 2. Joe once sent the police on Leo and Max, but he later regretted this decision. The family have helped Leo and his family at several occasions. In Season 3, however, Leo ends up living with at the Hawkins, which helps with his bonding with the family, especially Sophie, who we see Leo read the Little Mermaid to, while they both sit together on the sofa.
- The memory of his mother playing peek-a-boo to him is his most played back memory.
- According to Fred, when he was younger, he loved to collect dead leaves.
- Three years before the show began, Leo allegedly was a Junker, along with Salim Sadik. He even bailed him out of jail, when Salim was arrested for illegally modding Synths.
- Leo's Headcrack forum name is: User885
- Both of his parents committed suicide, though at different times and for different reasons.
- In Season 2, we learn that the base Leo and the Elster's have set up, is somewhere between Hemel Hempstead and St. Albans, in Hertfordshire.
- He was initially part human and part synth due to the synth components added to his brain to save his life. Then Hester stabbed him in the back of his head and those synth parts were damaged and consequently removed. This led everyone to think he was fully human again, even if he healed surprisingly fast, without any kind of brain damage, and was much stronger than expected. It was revealed in the Season 3 finale, that his synth blood and his human blood had mixed, altering his DNA and somehow infusing it with synth genes, which are now an integral part of his genetic code. This confirms that Leo is still partly synthetic, and that his synth genes were transmitted to his daughter with Mattie, who is confirmed to be half-synth and half-human as well.