The Hero of the story, Kazuki is a very well-meaning guy that enjoys helping people and does so by utilizing the gift of his Kakugane to create a Busou Renkin.
Bad Ass Normal: Before getting his powers, facing down a giant snake-like homunculus with nothing but a steel pipe! Guy's got some guts, even though getting them ripped out of him doesn't do him any good, he still manages to cope with it.
Deliberate Injury Gambit: Because he doesn't have a heart, Kazuki will oftentimes take a normally lethal hit to the torso in order to deliver a blow of his own.
The Dulcinea Effect: Got his foo' self killed trying to save a chick he didn't even know.
The Messiah: He's nice to everybody, he tries to save everybody, and even helps people who were killing him not five minutes before, even people who were killing him five minutes previously, then stop, then betray the truce, he'll still help them!
Walking Wasteland: His Kakugane is actually the third Black Kakugane, thus giving him the power to counter Victor, though almost at the cost of his life-drain aura becoming stronger and killing everybody else.
Belated Backstory: Her origin is not revealed in the manga until the final issue, where it's revealed she's the only person in her school who survived a homunculus attack, and ended up killing the homunculus (who had posed as a fellow classmate) with the Valkyrie Skirt, using the Kakugane which was being used to heal her wounds. She gained both her scar and her hatred of homonuculi during the incident.
Defrosting Ice Queen/Tsundere: She started out as somewhat cold to Kazuki, but starts growing both attached and angrier whenever he does something really stupid.
Don't Fear The Reaper: Her Busou Renkin's sub-name is Death Scythe, she's pretty to boot.
Badass Normal->Badass Abnormal: In the second episode, he is riding around totally calmly on Washio's back, even when Washio is attacking and defending - from a few hundred feet up in the air. Including perfectly holding his balance during dives and blurringly-fast maneuvers. Not bad for a guy with an Incurable Cough of Death. Then he becomes a homunculus and gains his Busou Renkin...
Combat Sadomasochist: One of the saner examples of this (and more of a masochist than sadist), but he has shown what seems like arousal in reaction to injury, and on the sadist front, look at his commentary after eating his family.
Do Not Call Me Paul: Ever since he became an homunculus, he no longer responds when called "Koushaku Chouno". He only makes an exception to his Worthy Opponent Kazuki though.
Glass Cannon: Can blow people to smithereens with his Busou Renkin, Near-death Happiness, but suffers from a severe lack in stamina due to his disease.
Immortality Immorality: Hommunculi have to eat people, but he doesn't, its the desire of the homunculi to become human that drives them to consume human flesh, since he hated his human life, he doesn't have to eat them.
Offstage Villainy: Its indicated that in order to transform himself, people had to die, including children, although Chouno didn't kill them himself (his minions probably did), but after that, he doesn't really do anything evil (although he makes threats that sound like those of an Omnicidal Maniac).
This Is My Name On Foreign: Chou means butterfly in Japanese (the full surname would translate to "butterfly field") and Papillon is the French word for butterfly.
Trouser Space: He likes hiding things in his crotch... a little too much.
Charles Atlas Superpower: His Renkin, Silver Skin, only helps his defense, all his earth shattering punches and acrobatics come from hard work and dedication.
The Charmer: Bravo Secret Art! Captain Bravo...Kiss!
Stone Wall: He tries to compensate for having a purely defensive Busou Renkin with impressive barehanded-combat skills, but the fact remains that he's better at taking hits than dishing them out.
Wrestler in All of Us: Considering that he specializes in unarmed close combat, it's not that surprising that he pulls off some wrestling moves, like an Octopus Stretch and an Argentinean Backbreaker.
Jerk with a Heart of Gold: I understand you think Kazuki's stupid, but do you need to be such a gigantic prick to him?
Weak, but Skilled: Takes down a lot of people with his relatively weak abilities using his brains and speed.
Wrong Genre Savvy: Thinks that he's the Romantic False Lead and Veronica between Kazuki and Tokiko, he really isn't, Tokiko treats him as a mild annoyance and is somewhat glad to see him again, Kazuki is completely oblivious to his aggression and talks about what great friends they are. Kind of veers into All Love Is Unrequited territory.
Walking Wasteland: It's like breathing to him; even if he wanted to stop it, he can't.
Woobie, Destroyer of Worlds: Wants to destroy all things related to alchemy because the Alchemist Army turned his daughter into a Homunculus and sent her out to kill him.
Moon Face
Voiced by: Tomokazu Seki (JP), Christopher Corey Smith (EN)
Originally named Lunare Nikoleav, Moon Face is a homunculus with a moon-shaped head and a higher-up of LXE He is depicted as constantly cheerful, rarely seen without smiling, and he uses the catch phrase "Moon~" whenever possible. After LXE is defeated, Moon Face is put into custody by the Alchemy Warriors, and later sent to the Moon with Victor and the other homunculi. Moon Face joined the LXE a hundred years before the start of the series, when he came from Russia to Japan for reasons unknown.
Meaningful Name: his head looks like a moon his name is also a play on "moon phase", which refers to his Buso Renkin's ability to create a duplicate representing every phase of the moon during a month.
His original name also counts, being similar to "lunar", meaning "of the moon".
Shout Out: Watsuki stated that he got the idea of Satellite 30 from the character Agent Smith from The Matrix Reloaded.
Dr. Butterfly
Voiced by: Katsumi Chou (JP) David Lodge (EN)
Around a century ago back when Bakushaku Chouno was a normal human, new sciences and technologies were flooding in from all over the world. One of them was alchemy which most people dismissed as charlatanry, however Bakushaku sensed there was more to it and so he began to delve into its mysteries. To his disappointment he found that there were limits to how far he could go on his own. His studies had consumed a fortune and years of his life went by until he discovered the homunculi and the Kakugane which led him to a dead end. However, not long after he met Victor Powered, a traitor of the alchemist warriors, the two then joined forces. Victor was severely injured so in exchange for his knowledge of alchemy, Bakushaku promised to heal him when he had finished his research.At some point later Bakushaku became a humanoid homunculus and discarded his identity, now calling himself Dr. Butterfly. He then went on to found the L.X.E.
Animal Motif: The Moth despite being called Dr. Butterfly
