BEWARE OF SPOILERS. Due to the nature of the show with its many Walking Spoiler characters, twists and turns, no spoilers are whited out so a page of pure white can be avoided.
The DHARMA Initiative
The leader of the DHARMA Initiative on the Island and also worked as a Mathematician.
- Alcohol-Induced Idiocy: Following a fight with Amy, Horace gets drunk and starts setting off dynamite early in the morning.
- Character Death: He dies in the Purge.
- Dies Wide Open: After being gassed during the Purge. Ben closes his eyes as a sign of respect.
- Drowning My Sorrows: After finding out that Amy kept Paul's ankh, he argues with her and gets drunk as a result.
- Extreme Doormat: Horace lets everyone walk right over him, especially Radzinsky.
- Hippie Teacher: Only he's an administrator and has unruly subordinates.
- Hollywood Nerd: Type 1.
- Nice Guy: He's a perfectly pleasant person, and the only Dharma member that Ben seems to have liked.
- New-Age Retro Hippie: Like many of the Dharma members.
- Posthumous Character: He was killed during the Purge, but appears frequently in flashbacks and the time-travel storyline in season 5.
- Reasonable Authority Figure: Pretty much the reason the far-less-reasonable Radzinsky usurped his position.
- Second Love: For Amy, and he's very insecure about it.
- Stupid Boss: He lacks authority or respect, and can't even lie convincingly. He also drunkenly starts blowing up trees after a fight with Amy.
A member of the DHARMA Initiative who worked at the Flame station in 1977 as Head of Research, enjoying a relatively high leadership position within the Initiative.
- Arc Villain: Radzinsky is the main villain of the Dharma Initiative arc during season 5.
- Bald of Evil: He's bald on top with longer hair around the side of his head.
- Beard of Evil: He has a full beard.
- Berserk Button: Don't threaten the Swan.
- Big Bad: Of the season 5 Dharma arc.
- Character Death: Radzinsky dies off-screen, blowing his brains out in the Swan Station according to Kelvin.
- Control Freak: He's explicitly mentioned in his casting call as 'controlling'. Horace never truly has a leash on him, and Radzinsky swiftly takes charge when Horace tries to calm him one too many times.Horace: Hey. Hey! Stop! Damn it, stop. That is an order. I'm still in charge here.Radzinsky: No, you were in charge, Horace. But if we're gonna protect our people and all the work we're doing here, you don't have the stomach for what happens next.
- Driven to Suicide: Some time after the Purge, but before Desmond's arrival on the island.
- Even Evil Has Standards: Looks mildly shocked when Phil punches Juliet.
- Four Eyes, Zero Soul: He wears a set of thick, nerdy glasses but that doesn't make him harmless. He's an obsessive maniac who won't hesitate to kill.
- For Science!: His main reason behind wanting to build the Swan.
- Hair-Trigger Temper: Even the slightest disruption to his day is enough to send him into a rage.
- Hot-Blooded: It doesn't take much to have him reaching for his gun.
- Jerkass: Radzinsky is rude, short-tempered, bloodthirsty, needlessly sarcastic, overly controlling and paranoid.
- Laser-Guided Karma: Okay, Stu, you love your precious Swan station so much? How about you spend the rest of your life basically imprisoned inside it, in solitude, until you go insane and blow your brains out?
- Photographic Memory: Part of what makes him such a genius, and how he was able to map out the lockdown mural.
- Posthumous Character: He blew his brains out in the Swan station long before the events of the series, but appears via time travel.
- Too Dumb to Live: If your men start dying because of electro-magnetic energy, you should usually stop trying to release all of it.
- Well-Intentioned Extremist: Like the rest of the Dharma Initiative, there are some noble intentions behind the lunacy.
A member of the DHARMA Initiative who worked in security under the authority of James "Sawyer" Ford, who was using the alias of "Mister" LaFleur.
- Big Ol' Eyebrows: They're...very prominent.
- Bound and Gagged: By Sawyer after he comes to him about the video evidence.
- Character Death: During the incident, flying magnetic poles shoot right through him.
- The Dragon: To Radzinsky, eventually.
- Evil Is Petty: He's a rules freak who chews out his co-workers for having a bit of fun on the job.
- Impaled with Extreme Prejudice: By flying magnetic poles!
- It's Personal: With Sawyer, after the whole LaFleur deception is revealed. Phil seems very angry that Sawyer Bound and Gagged him.
- Jerkass: He's usually in a bad mood, although from time to time he exhibits a little bit of niceness.
- Posthumous Character: Died many years prior to the start of the series proper.
- Would Hit a Girl: He strikes a tied-up Juliet hard enough to make her bleed, for the purposes of making Sawyer talk.
A member of the DHARMA Initiative on the Island in the 1970s and was the first member of the Initiative to meet the time travelling survivors. She was the wife of Horace Goodspeed and the mother of Ethan Rom.
- Character Death: Word of God is that she died in the Purge.
- Happily Married: To Paul, and later has a not-entirely-happy marriage with Horace.
- Mama Bear: For Ethan.
- Lady Macbeth: In her few appearances, she proved to be much more bloodthirsty than her husband.
- Posthumous Character: Long dead before the events of the series begin.
- Ugly Guy, Hot Wife: She married somewhat below her station.
- Wham Line: The revelation that she's Ethan's mother.
- What Happened to the Mouse?: According to Word of God, she died in the Purge.
Pierre Chang's wife and the mother of Miles Straume. She was a member of the DHARMA Initiative and lived on the Island in the 1970s.
The father of Benjamin Linus, whom he regularly abused, both verbally and possibly physically, and berated as a child. He was employed as a DHARMA Initiative "Workman," and his uniform featured the Swan station logo.
- Abusive Parent: To Ben, who he abuses verbally and physically.
- The Alcoholic: After finding out he's to be a janitor for the Dharma Initiative, he begins drinking heavily.
- Alcoholic Parent: Ben often comes home to find him passed out in an alcoholic stupor.
- Asshole Victim: While he does show a slightly more likeable side right before his death, he was still an abusive, self-pitying jerk, so it's hard to feel sympathetic when Ben gasses him to death.
- Butt-Monkey: Things never do go very well for him; his beloved wife dies, he feels humiliated in his job, becomes an alcoholic and is eventually murdered by his son.
- Character Death: Ben murders him with a poisonous gas canister during the Purge.
- Despair Event Horizon: After Emily's death, he falls into depression and self-loathing.
- Drowning My Sorrows: For the rest of his life.
- Hair-Trigger Temper: He flies off the handle whenever Ben messes up even a little.
- Hidden Depths: In the flash-sideways, he's still bitter but treats Ben much better. In the timeline-actual, he has a little more complexity than most abusive parent characters. Sure, he's a bastard, but he knows he's a bastard. Roger seems to be stuck in a cycle of anger, despair, self-loathing and alcoholism. He is also very distressed and authentically worried when he finds out Ben got shot by Sayid. It's one of the few times where he actually acts like a real father.
- Jerkass: An abusive drunk who easily takes offence at harmless suggestions.
- Jerk with a Heart of Gold: As bad as he was, he later seemed to genuinely regret how much of a bastard he'd been to Ben and tries to make amends. Unfortunately, Ben is burning his bridges at that point.
- Karmic Death: Killed by the son he abused and tormented.
- Posthumous Character: He's first seen as a skeleton.
A member of the U.S. Army and later the DHARMA Initiative. He manned the Swan station after his arrival on the island, originally with his partner Stuart Radzinsky, by himself for a time, and later with Desmond.
- Beard of Sorrow: Kelvin was deeply depressed and disillusioned during his time in the Swan station.
- Character Death: Desmond tackles him in a rage, knocking his head against some rocks and killing him by accident.
- Death by Falling Over: When Desmond tackles him, Kelvin hits his head on some rocks and dies.
- Drowning My Sorrows: Inman deals with his sense of hopelessness by getting drunk in the Station.
- Jaded Washout: By the time Desmond meets Kelvin, he's become a disillusioned and bitter man.
- Jerkass: He's pretty condescending and gets irritated when Desmond questions him.
- Just Following Orders: Implied to be part of the reason he became a Jaded Washout.
- Posthumous Character: He's killed by Desmond, just a few minutes prior to the plane crash and thus the beginning of the series.
- Manipulative Bastard: Manages to convince Desmond to stay underground pushing a button, effectively stealing three years of his life so that he could repair a boat in secret. And he's also the one who drove Sayid to start torturing.
- Screw This, I'm Outta Here!: Kelvin has become disillusioned with the button and decides to leave."Screw the button, man. Who knows if it's even real?"
- Shell-Shocked Veteran: He's haunted by his experiences during the Gulf War.
- Small Role, Big Impact: He drives Sayid to become a torturer, and is therefore responsible for everything that leads to. His deception of Desmond causes the latter to leave the Swan at a critical moment, and this causes the crash of Flight 815.
- Tempting Fate: He orders Desmond not to leave the Swan, right after learning he was kicked out of the army for disobeying orders.
- Wham Line: He reveals to Sayid in a single line that he speaks Arabic, meaning he was capable of performing the interrogation he made Sayid do.
Ben's childhood friend on the Island.
- Aborted Arc: Along with Alex, Darlton said that Annie was one of the two most significant women in Ben's life. They even said, "Annie is going to prove to be very significant in Ben's life" but she's never seen again. Michael Emerson, Ben's actor, expressed some disappointment they never returned to Annie's story.
- Childhood Friends: With Ben in the Dharma Initiative.
- Chuck Cunningham Syndrome: She was meant to be very important to Ben's story, but disappears entirely after a single episode. She was apparently evacuated with all the other Dharma children in 1977 and didn't return.
- Only Friend: To a young Ben, who wasn't exactly the most out-going of kids. Annie was the only person to befriend him.
A chemist and DHARMA Initiative member who performed interrogations.
- The Aloner: Lives all the way on the outskirts, completely in isolation from the rest of the Dharma Initiative.
- Cold-Blooded Torture: Oldham is given a good bit of build-up, so it's expected, but he uses a chemical mixture instead of physical torture. Traumatic, sure, but nothing compared to what Sayid's done.
- Creepy Monotone: Never raises his voice.
- The Dreaded: Sawyer is very wary of taking Sayid to him, referring to him as a psychopath.
- Evil Counterpart: To Sayid. Sawyer even remarks,"'He's our you."
- Four Eyes, Zero Soul: He wears a big nerdy pair of glasses, and is widely considering to be a complete psychopath.
- Soft-Spoken Sadist: Maintains William Sanderson's soft Southern drawl even when interrogating prisoners.
- Torture Technician: He's set up as this, but he doesn't use overly extreme methods and relies on a chemical mixture.
- What Happened to the Mouse?: It's unknown whether he died in the Purge, defected to the Others or just left the island.