The Oxford Five
Auggie Salazar
Dr. Augustina "Auggie" Salazar
Played By: Eiza González
A scientist specializing in nanotechnology.
- Adaptational Angst Upgrade: In the book, Wang Miao had already developed nano-fibers, and now the technical challenge he was working on was making their production economically scalable. When he shut down the project, his technicians were delighted because he'd had the machine running non-stop and it was long overdue for maintenance and upgrades. He had plausible deniability that the pause was for practical reasons and was receiving emotional support (sort of) and a sense of safety from Lao Shi's protective services. In the show, Auggie shuts down the project seconds after its first practical demonstration, offers no explanation for the decision, and is threatened with deportation for it. After initially meeting with her about the countdown, Clarence Shi leaves her to her own devices and only monitors from a distance.
- Insufferable Genius: Subverted. She's an abrasive genius, but not out of arrogance and rather out of social awkwardness and anxiety.
- Jerk with a Heart of Gold: She's a firmly moral person, but she's also standoffish, blunt, and somewhat abrasive.
Saul Durand
Dr. Saul Durand
Played By: Jovan Adepo
A physics research assistant.
- Agent Scully: He fervently denies anything out of the ordinary is going on, even insisting that the San-Ti blacking out the night sky was simply a deep fake.
- Brilliant, but Lazy: He's very smart, but content to slack off and party rather than apply himself.
Jack Rooney
Jack Rooney
Played By: John Bradley
A snack magnate and scientist.
- Bunny-Ears Lawyer: He's a scatterbrained eccentric, but he established a successful snack franchise that made him rich.
- Death by Adaptation: Jack is killed in episode three, whereas his book counterpart exited the narrative without a scratch.
- Jerk with a Heart of Gold: He's a bit insensitive and crass, but he's also a very caring and loyal friend.
- Plucky Comic Relief: He's very much a comic relief character, serving to provide levity in an otherwise extremely serious and grim show.
Jin Cheng
Dr. Jin Cheng
Played By: Jess Hong
A curious and brilliant theoretical physicist.
- Nice Girl: She's generally kind and empathetic, and lacks the rest of the Five's more negative qualities.
Will Downing
Dr. Will Downing
Played By: Alex Sharp
A timid physics teacher.
- All Love Is Unrequited: He has a crush on Jin that's lasted years, but he was too scared to ever act on it until it was too late.
- Extreme Doormat: He's so meek he lets his students walk all over him. Jack calls him out on this, pointing out Will always lies down and accepts misfortune rather than trying to change his situation.
- Secretly Dying: In the second episode, he reveals to Jack he's dying of pancreatic cancer, but hasn't told anyone else.
Strategic Intelligence Agency
Clarence Shi
Clarence Shi
Played By: Benedict Wong
"Be glad you're not a scientist. It's a shit time to be a scientist."
A cynical SIA agent investigating recent strange phenomena.
- Beard of Sorrow: He has a barely groomed beard that reflects his disheveled appearance. It's implied he's become depressed after the death of his wife.
- Deadpan Snarker: He's very prone to dryly sardonic remarks.
- Hardboiled Detective: He's a hard-drinking, smoking detective pursuing shadowy, powerful figures. The only exception to the rule is that he's a spy rather than a private detective or cop.
Thomas Wade
Thomas Wade
Played By: Liam Cunningham
The head of the Strategic Intelligence Agency.
- Ambiguously Evil: He's on humanity's side, but he's enigmatic, ruthless, and has a quite sinister demeanor.
- Bad Boss: He fires an employee for complaining about Clarence's smoking on the grounds that he doesn't care enough about his actual job.
Collins
Collins
Played By: Gerard Monaco
Clarence's partner.
- Audience Surrogate: His purpose in the pilot is for Clarence to have an excuse to exposit to the audience.
- Bumbling Sidekick: Downplayed. He comes off as much less on the ball than Clarence, but not incompetent.
The San-Ti and Allies
In General
- Adaptational Badass: As explained by a San-Ti scientist in the book, sophons have a limited set of ways to affect Earth: interfering with particle experiments by ramming the particles, leaving black or white imprints in camera film and retinas by passing through them, becoming opaque to visible light by expanding to, e.g., beach ball size, and becoming opaque to background radiation by expanding to global size. They are much more versatile in the show, able to cause satellite monitoring malfunctions, scrub ETO agents from camera footage and real-time human sight, and communicate via radio waves. This also makes the ETO more badass by proxy, as they've been in operation longer and more actively, with the world governments on their tail sooner, but completely untouchable until the San-Ti withdraw active support.
- Adaptational Dumbass: In the book, the San-Ti figured out humans can lie, and other aspects of human psychology, years prior to the present day (201X) and cut off contact with the ETO out of suspicion. In the series, Mike Evans is reading them fairytales in 202X and they continue to struggle with basic concepts in human psychology.
- Adaptational Wimp: In the book, the San-Ti almost exclusively targeted theoretical physicists, because only they could make the breakthroughs in fundamental physics that would allow humans to develop technology capable of threatening the San-Ti. Wang Miao was unique among applied physicists in being targeted, because his nano-fibers could potentially allow humanity to develop space elevators and spread out through the solar system faster than the San-Ti could send enough sophons to cover that much space and continue to interfere with all their particle experiments. Here, scientists more broadly are enough of a threat to be worth targeting. A cyberneticist is given as an example of a target, and Mike Evans fosters mundane anti-science trends such as 5G conspiracy theories and anti-vaxxers.
- Aliens Are Bastards: The San-Ti are so smug and contemptuous toward humanity that it's difficult to empathize with them at all, even knowing their tragic backstory.
Sophon
Sophon
Played By: Sea Shimooka
An artificial intelligence created by the San-Ti.
- The Stoic: She remains composed even while decapitating Jack's virtual avatar.
The ETO
Ye Wenjie
Ye Wenjie
Played By: Rosalind Chao, Zine Tseng (young)
An astrophysics prodigy who contacted the San-Ti in the 1970s.
- Anti-Villain: Her life was full of tragedy and she remains sympathetic in the present day, but she still betrays mankind to the San-Ti.
- Despair Event Horizon: In a shocking twist of fate, Ye Wenjie is confronted at the labor camp by the same girl who killed her father in the public square execution years before. Apparently the girl outlived her usefulness to the state, and so they imposed on her the same exile and suffering as Ye Wenjie. Even so, the girl clings so tightly to her hatefulness that she boasts she would kill Ye Wenjie's father all over again if she could. It is this moment that causes Ye Wenjie to consider humanity to be beyond redemption without a greater outside force to control it.
- Madden Into Misanthropy: A life of non-stop trauma and betrayal caused her to betray humanity to the San-Ti in the hopes they would save mankind.
- Walking Spoiler: It's very hard to talk about her without spoiling a lot of the show.
Mike Evans
Mike Evans
Played By: Jonathan Pryce, Ben Schentzer (young)
A mysterious oil magnate connected to the San-Ti and Ye Wenjie.
- Adaptational Nice Guy: In the books, Mike Evans was a Misanthrope Supreme who hated the human race and openly wanted the aliens to wipe us all out as penance for what we've done to the planet. Here, he's an Affably Evil Cool Old Guy who, like Ye Wenjie, merely wants the San-Ti to fix the flaws inherent to human civilization and is horrified when they decide to Kill All Humans instead. His death is also portrayed sympathetically in the show, while in the book he is Killed Offscreen and never expresses remorse for his actions.
Tatiana Haas
Tatiana Haas
Played By: Marlo Kelly
A cultist protected by the Sophons.
- Affably Evil: She's quite polite, soft-spoken and even kindly, but she's ruthless and fanatically loyal to the San-Ti.
- Hero Killer: She murders Jack for refusing to join the ETO.
Others
Raj Varma
Prithiraj "Raj" Varma
Played By: Saamer Usmani
A naval officer and Jin's boyfriend.
Denys Porlock
Denys Porlock
Played By: Adrian Edmondson
Auggie's boss.
- Locked Out of the Loop: Since he has no idea about the San-Ti or that they're threatening to kill Auggie, he's flabbergasted when she abruptly pulls the plug on her project for seemingly no reason.
- Nice Guy: He's fairly friendly and congratulates Auggie on her successful project.
Tang Hongjing
Tang Hongjing
Played By: Lan Xiya
A ruthless and fanatical young Red Guard during the Cultural Revolution.
- An Arm and a Leg: Worked in a hard labor camp after the Cultural Revolution, where her arm was gruesomely and painfully amputated without anesthesia.
- Unwitting Instigator of Doom: When Ye Wenjie encounters her again after many years, she asks the former Red Guard if she feels any regret for beating Ye's father to death. Tang defiantly states that despite the suffering she has endured, she would gladly "scythe him like wheat" again. Her utter lack of remorse further embitters Ye toward humanity, and leads to her contacting the San-Ti.
Vera Ye
Dr. Vera Ye
Played By: Vedette Lim
A scientist who mentored the Oxford Five.
- Psychic-Assisted Suicide: She's forced to commit suicide by the San-Ti.
