Head of the American contingent. Frank is cynical and ruthlessly pragmatic. His first act in the book is engineering a riot and the death of his old friend, John Boone, but there's more to him than that.
Be All My Sins Remembered: He is actually angered by the fact that Maya falls in love with him some time after the night in Nicosia, because in his opinion he doesn't deserve it.
Beneath the Mask: He is very, very rarely open about his true feelings, and behind the mask he has a lot of anger and contempt for people, even the ones he feels the most affection for.
Cunning Linguist: Learning new languages comes easily to him. (Granted, Michel thinks his French is awful.)
It's All My Fault / My God, What Have I Done?: Not a sudden realization, but a gradual one - After Nicosia he slowly comes to realize that he screwed everything up for everyone, and that he is the only one who knows it.
Jerk with a Heart of Gold: When we see his second POV section, he's a much more complicated person than the villain he seems to be in the prologue.
Manipulative Bastard: He's not as charismatic as Boone, but the first chapter makes it clear that he's been playing various groups (particularly the Arabs) like a fiddle.
The Resenter: He grows to despise Boone for walking on Mars first, and then being in a relationship with Maya.
Used to Be a Sweet Kid: Maya speculates this when she finds a biography that describes his early career as a young, idealistic public servant working for a program that was shut down by a corrupt politician. Cross between this and Maddened Into Misanthropy.
Famous for being the first person to set foot on the Red Planet. John Boone has an effortless charisma and charm that quickly makes him the de facto leader of the American contigent, and perhaps the First Hundred in gneral.
The Ace: First Man on Mars. He's also really charismatic, likable, and friendly.
Berserk Button: Religion, specifically Christianity. He views it as a political construct based on the history of the Bible's writing and gets very heated after an Easter service is conducted aboard the Ares, to the surprise of everyone who's used to easy-going friendly John.
Bold Explorer: He's so eager to be part of Mars exploration that he charms his way into the First Hundred expedition despite being over the lifetime acceptable exposure to radiation.
Functional Addict: He's addicted to the fictional drug omegendorph, but it doesn't seem to impair him too much.
The Leader: Type IV, Charismatic. He can easily get others to follow him and defuses tensions and arguments through his charm.
Magnetic Hero: Given enough time, John Boone can get along with anyone, provided they don't have a corporate agenda or are named Frank Chalmers. He can even get Ann, who admits she sympathizes with the Reds who tried to assassinate him, to like and trust him. Coyote says it's because John was so good at being convinced of other people's point of view (while putting his own spin on it) rather than the other way around.
Odd Couple: With Chalmers, but it eventually falls apart.
Shrouded in Myth: After his death. One of the inter-chapter sections transitions from Boone's biography to stories of him, Paul Bunyan, and Big Man. Political groups later invoke his name to back up their position.
The leader of the Russian contingent. A complex individual who takes a great interest in the power dynamics of the First Hundred.
Determinator: She drives the First Hundred in their escape from the metanats in 2061. Later, multiple people credit her with their survival.
The Fog of Ages: In Blue Mars she experiences jamais vu (the opposite of deja vu) and presque vu (i.e. "it's on the tip of my tongue).
Heterosexual Life-Partners: With Nadia, described as being like sisters—they don't get along and aren't much alike and yet are intimate.
Manipulative Bastard: She considers sexual and romantic relationships as a means to an end, both in her early career as a cosmonaut and with John and Frank. Subverted, though, in that she also gets heavily emotionally involved in several of them, even while using them as a means of influence (thus sometimes leading to a very chaotic power situation...)
Masochism Tango: All of her romantic relationships, more or less. Blatantly lampshaded by Nadia and Arkady.
Too Much Alike: With Frank, both of them being manipulators with a constant eye on the power dynamics of the colonists.
Tsundere: With the justification that she has Bipolar Personality Disorder.
Nadezhda "Nadia" Chernyshevski
A Russian engineer who is responsible for the design and construction of the first settlement. She's largely apolitical and is more interested in the challenge of building on Mars than revolution or terraforming.
Cincinnatus: She's pushed into politics against her will because she's the most moderate and trustworthy figure. Later, she becomes the first President of Mars.
Closer to Earth: (Or perhaps we should say Mars.) In her relationships with people like Maya, but also with the lively revolutionary Arkady, she's usually the more stable person.
The Engineer: Before going to Mars, she built nuclear reactors in Siberia. She's instrumental in design and construction of the Mars habitats.
Heroic Safe Mode: After finding Arkady's incinerated corpse in the first revolution, she's relieved at the necessity of frantic engineering and repairs because it allows her to not think about the horror going on.
Ms Fixit: Everyone calls her when they need to fix something or figure out a solution to some problem in construction or design.
Only Sane Man: While everyone else is running around with radical viewpoints, Nadia focuses on the job at hand and is rather exasperated at all the petty power struggles.
Opposites Attract: She's very sensible, exasperated with melodrama, and levelheaded, and she falls in love with the wildly revolutionary Arkady.
Another Russian engineer. Arkady is a visionary or a revolutionary who sees Mars colonization as a way to reinvent human society.
Batman Gambit: He banked on using Phobos to set up the revolution. It was a safe bet that he would be the leader of the group that was left there, because nobody else wanted to stay on Phobos.
Be Careful What You Wish For: From the start he wanted to create a new society and encouraged revolution. He dies horribly shortly after the 2061 rebellion begins, and that attempt is brutally crushed by the transnat-controlled UN.
Crazy-Prepared: He and his team secretly turned Phobos into a rocket in case it was ever used as a weapons platform. He's right, and Nadia brings it down in 2061.
A physicist who wants to terraform Mars from the get-go. He's not that interested in politics and his main motivation is pure scientific curiosity, but as the situation on Mars heats up his neutrality backfires on him.
All Love Is Unrequited: Understated, but he's always trying to get Ann Clayborne to like what he's doing, without success. In Blue Mars, both of them realize that they have this towards each other.
Crazy-Prepared: Once the second revolution breaks out in Green Mars, it turns out he had spent the preceding years preparing for a number of large-scale contingencies, including making possible the open-air evacuation of an entire city by having raised the oxygen levels in the atmosphere and making tens of thousands of carbon dioxide filter masks.
For Science!: He's accused of irresponsibly wanting to terraform Mars without considering the consequences, especially by Ann.
Mad Scientist: He gets nicknamed this during the second revolution.
Meaningful Name: He is named after a flower, saxifrage, and the name means "rock-breaker"; this is fitting, since he is the character most eager to destroy Mars's native rocky terrain and create one that can support plant life, and because he is the primary ideological opponent of the geologist, Ann Clayborne, who has the opposite desire. The name Russel is probably a homage to Bertrand Russel, a philosopher who prized logical scientific thought.
Phrase Catcher: "Sax must love this" about the chaotic areological effects of 2061—aquifers bursting, nuclear explosions, etc—because they're probably adding heat and oxygen to the system. (He doesn't.)
Took a Level in Badass: He starts as an apolitical biologist who wants to terraform Mars basically just to see if it can be done. After being abducted and tortured by the Secret Police in Green Mars, he becomes a primary leader in the second revolution and is called "General Sax."
Ann is a geologist/areologist who advocates for keeping Mars as free of human alteration as possible. She finds the planet beautiful as it is now and is disgusted by the idea of terraforming it. This viewpoint is the genesis of "the Reds," one of the political factions that come about.
Driven to Suicide: At the end of Red Mars she tries to freeze herself to death, thinking that her son is dead and she's to blame for Frank's death. Her husband Simon stops her.
It's All My Fault: She blames herself for Frank's death. She got distracted while driving, the car got stuck, and he was swept away in a flood trying to free it.
Meaningful Name: She is in love with earth and rocks more than anything else, and her name "clay born" reflects it. Part of a trio of rock-themed names with her husband and son, Simon and Peter.
Sugar and Ice Personality: She's usually depressed or fractious, but she really loves geology (or areology, as it is on Mars). "Depressed" as in actual clinical depression.
The leader of the farmers. Nobody seems able to figure her out, but her belief in terraforming goes beyond scientific into a religious movement around the concept of viriditas, or green strength.
Mars Mother: Although she's not described with the physical characteristics, she is fertile (in the sense that she has a lot of genetic offspring, see below) and is the leader of the farm team. She also creates a religion around the worship of Mars itself and one person in Red Mars repeats a rumor that she's constantly pregnant.
Meaningful Name: "Ai" means "love." Her movement is all about mutual love and respect for other people and the planet.
Never Found the Body: Her compound is attacked in Green Mars, but nobody finds her body and many refuse to believe she died. Sax seems to be saved by her while lost in a blizzard, but he thinks later that it was probably a hallucination.
Stalker with a Test Tube: She collects DNA from various people, including John Boone, and artificially reproduces with it.
What the Hell, Hero?: She gets chewed out by the others for several things, like vanishing to a hidden colony when the rest of the First Hundred wanted her help with the deteriorating situation, or secretly creating dozens of children from their DNA without asking permission.
The psychologist assigned to interact with and monitor the crew of the Ares, which quickly proves to be an overwhelming task.
Sanity Slippage: After landing on Mars. He loses huge chunks of time from his memory and considers himself to be losing his mind until Hiroko and the farm team spirit him away to Zygote.
You Can't Go Home Again: He longs to return to his hometown of Provence. When he gets there, it's so changed that he feels even worse.
Vladimir "Vlad" Taneev
A member of the Russian contingent who was recognized for brilliance in both medicine and economics. He continues to be very innovative in both areas after settling on Mars, and his work is a major catalyst for change on both Mars and Earth as the story progresses.
Polyamory: with Marina and Ursula. Probably. None of the other characters are ever really sure.
An American biologist. When the transnats start taking control of the U.N. and Mars, she allies herself with them, putting her at odds with the rest of the First Hundred.
Category Traitor: Considered such by the other First Hundred but for quite justified reasons. Still, they're rather shocked when Maya kills her.
Deader than Dead: She survives the destruction of the elevator and Clarke being shot to Jupiter. So when Maya's group rescues Sax, Maya kills her with a bomb.
Face-Heel Turn: She's the only one of the First Hundred who joins the metanats during the revolution of 2061, even while they're trying to kill all the First Hundred.
The Fundamentalist: Although it's not a major part of the conflict between her and the other characters, she's a devout Christian, and her bits are broadcast on Christian television.
Money, Dear Boy: She sees Mars as a gold mine and allies herself with the metanats.
Smug Snake: Frank calls her a "tin god" who thinks that she's taken control of Mars and put herself above the rest of the First Hundred.
Desmond "Coyote" Hawkins
Coyote is Hiroko's ex-boyfriend whom she secretly brings on the voyage to Mars. He becomes more prominent in Green Mars, helping to run the underground communities hiding from the metanats.
Big Damn Heroes: With Michel in helping Nadia's group to escape Cairo while the transnats are hunting them.
Do Not Call Me Paul: At one point on his road trip with Nirgal, he gets cynical and demands that Nirgal call him Desmond. A while later, his mood picks up and he basically says "Desmond? Who's Desmond?"
First Love: The fact that he's Hiroko's college boyfriend has a lot to do with why he's there.
Parental Substitute: He acts as a surrogate father to Nirgal since the children have been given a collective upbringing regardless of which ones are their parents. Later, they learn that Coyote is Nirgal's actual father.
Rebel Leader: He's involved with the Red revolutionaries and "hidden" colonists and meets with John to talk about all the sabotage that's going on.
The natural-born son of Ann Clayborne and Simon Frazier. He's one of the first children born on Mars. He later joins the Mars First movement and holds Green philosophies, putting him at odds with his mother.
Meaningful Name: Of course Anne would give her child a name that means "rock".
No One Could Survive That: The odds of him surviving the jump from the elevator are astronomically against him; his mother assumes he's dead for a long time. But a shuttle piloted by rebels somehow manages to find him during the (admittedly very long) fall. Thoroughly lampshaded.
Thrown Out the Airlock: Well actually he jumped, on purpose, as a last ditch attempt to survive because the thing he was in was going to crash out of orbit.
Genetic son of Hiroko and John Boone. He becomes a revolutionary for the Reds.
Fish out of Water: On Earth in a big way. He was born and raised in Mars's low gravity. When he tries running on Earth, he's gasping like a fish before long, and then he gets severely ill.
Missing Mom: After Hiroko vanishes, Nirgal goes as far as Earth to search for her.
Daughter of Kasei and another descendant named Esther. She is John Boone's granddaughter and uses his last name, which is significant because most of Zygote's children don't use last names at all.
It's All About Me: If you believe Nirgal and Maya, at least, who think that Jackie's shifts in opinion are about securing personal power.
Manipulative Bastard: even better at using seduction/relationships to get what she wants than Maya, and even more cynical and power-hungry than Frank.
Zoya "Zo" Boone
Jackie's daughter. She appears in Blue Mars. Although she travels the solar system to run political errands for her mother, the two of them don't get along.
Icarus Allusion: She enjoys recreational gliding and gets into a friendly competition with another flyer. When that flyer goes to far and plummets, Zo tries to save her and they both drown.
Jerkass: She's very dismissive and insulting towards just about everyone who doesn't share her opinions. Even when Ann sits down and explains to her exactly why she is interested in geology/areology, Zo dismisses it.
Jerk with a Heart of Gold: Despite the above, she goes out of her way to save someone's life on Mercury and again when a fellow glider falls. The second results in her own death.