I Am Not Left-Handed: Inverted "A lion boils even a rabbit with all its strength!" he goes all out even on punny ayakashi.
Idiot Hero: Somewhat. In most series he'd probably be considered a fairly smart fighter; he just stands out here because everyone else fights very intelligently and he tends to fight through instinct and pure power too often. His older brother and Tokine are the major foils.
What the Hell, Hero?: Once from Tokine for intentionally getting captured by Kokuboro, forcing his allies to endanger themselves to rescue him, and from Tokiko, minus a slap, for trying to save the school from an ayakashi swarm with a technique he had NO IDEA how to use and probably would have ended up killing everyone.
Tsundere: Mild version. Alternates between fanship fodder moments with Yoshimori, treating him as a coworker/classmate treating him like a kid brother, treating him like an annoying kid brother, beating him up for annoying her, and beating him up while crying her eyes out for worrying him, then playing the trope as straight as possible by beating him up while trying to apologize to him.
Weak, but Skilled: She isn't as strong as Yoshimori, but she's more accurate than he is.
to the point that her signature style switches from giant kekkai that she implodes around ayakashi to small, thin kekkai that she uses to stab them and hold them in place.
Why Did It Have to Be Snakes?: She's terrified of cockroaches. Probably not helped by the bug ayakashi that scarred her hand as a child, but fear of cockroaches also runs in the family.
Dissonant Serenity: Due to his older brother's frequent quarrels with their grandfather, living in the Yoshimori house is somewhat hectic, but he and his father rarely take notice.
The Smart Guy: From time to time, Yoshimori decides that his best plan is just to tell Zen what his goals are, then do whatever Zen says.
Telepathy: Limited by several things. Kekkaishi and possibly some other ability users block it and even detect or interfere with it. It also provokes a red right hand in the form of his eyes flashing demonic when he uses it. This is worse than it sounds as he needs to be close for it to work. Lastly, Zen is afraid that he will be ostracized even by the other Yagyou if they find out he is able to read their minds, so he does his best to conceal his ability, even when he has information that he desperately would like to share.
Atora Hanashimi
Captain Ersatz: Atora is apparently a Pokémon trainer who got lost and ended up in the Yagyou.
Bishonen Line: Starts out as a middle-aged old man, changes to a distinctly more attractive twentyish year old (with cool boots), then finally to a Cute Shotaro Boy.
How to best describe this sadistic little Really 700 Years OldBig Bad? Well, for starters he lost his memory and is always trying to get it back, and at the same time wants some sweet revenge on that evil big brother of his. How does he want to go about this? KILL EVERYONE IN THE URAKAI. Together with his Numbered minions, he masterminds and manipulates events behind the scenes as The King, an aged man, and as his current container, a young boy who can best be described as Little Mister High Octane Nightmare Fuel.
Abel And Cain: You might think Yumeji / Tsukihisa is the Abel to his Cain at first. Turns out, in comparison, Tsukihisa is much, much worse than Nichinaga could ever be.
Alas, Poor Villain: when his real motivations and the circumstances were revealed, it was VERY difficult not to feel sorry for him.
Complete Monster: At first, when nobody knew why he was doing anything. Turned out, this trope more applies to his elder brother, who is not even his real brother.
Heel Realization: [[spoiler: when his big brother possesses his favorite minion and sets wheels of plots in motion to make him essentially lose everything again, he remembers, its reveal bombed what happened, Nichinaga repents with death.
Hellish Pupils: with two irises in fact, that make him seriously unnerving.
Sugar and Ice: to Suigetsu. He loves her, a lot. He just really doesn't show it much until the end.
Sugar and Ice: to Suigetsu. He loves her, a lot. He just really doesn't show it much until the end.
The Kokubourou
Aihi
Affably Evil: She doesn't really exhibit much animosity—nowhere near as much as the other Kokubourou, that's for sure. Then we learn that she not only lived with a human man, but even fell in love with him, which is what prompted her study of humans.
A Form You Are Comfortable With: She once maintained her appearance as a human for the man she fell in love with, who was somewhat scared by the appearance of a walking flower in a kimono.
Humanity is Infectious: She gradually gained her interest in humanity from living and falling in love with a human man, which she couldn't quite manifest.
Lack of Empathy: Oh my God. One of the creepiest examples ever. He routinely treats Hime, the only being for whom he probably ever felt anything, so coldly, that you would be forgiven for thinking he has some sinister plan for her, and will discard her the instant she's not needed for it anymore (as he treats his minions). Actually, Byaku sincerely wishes to heal Hime, it's just that he so out of touch with others' emotions, that not only his reaction to his wife's bout of depression - after he disfigured her in an attempt to extend her life by magic - was calmly helping her to kill herself, he also simply fails to see why anyone might object to it.
Meaningful Name: "White," appropriate for his hair color. It also points back to his old identity; the "shiro" in "Shironuma" also means "white."
Really 700 Years Old: Though he looks like a man in his early thirties, He's actually nine years older then his friend, Matsudo who is a peer of Yoshimori's grandpa.
Epileptic Tree: Doubles as Fridge Brilliance, Shishio after his death tells his loyal henchmen Hoji, that he'll conquer hell, Since there's a long time between Rurouni Kenshin and Kekkaishi's timeline, it's possible that he did in fact do that, considering his strength, and was awarded the form of a high-ranked demon, (ignoring the anime version where he's a bug eyed freak who got scared of being caught), and began serving Kokubourou out of boredom. Since no one in his time was really an equal to him, he began to search for the one person who can truly give the "feeling" of having his life on the line, especially since he can beat most demons on a reflex.
Even Evil Has Standards: Believe it or not. He kills off two of his surviving subordinates when they take Tokine hostage, Scolding them for their "lack of aesthetic".
Expy: His bandaged form looks remarkably similar to Makoto Shisio from Rurouni Kenshin.
Hannibal Lecture: Delivers an extremely harsh one to Shishio. Also has the inability of having a conversion that doesn't involve messing the other's head. Fails with Yoshimori because he's too dumb to understand what he's trying to trying to get him to do.
Moral Event Horizon: From the moment you saw him, you knew he's bad news, then kills Gen when he was about to finish off another opponent, earning him a special place in Yoshimori's heart.
The Nose Knows: The whole reason Yoshimori and the previous Sumimura kekkaishi have used him as a partner. He's very good at sniffing out ayakashi before they can be seen.
Viewer Gender Confusion: He uses Japanese feminine pronouns in the original manga. In translations and the anime it's clear he's a guy.
The mangaka originally intended for Madarao to be female, but she never specifically said so and the anime used a male seiyuu. So she went with it and Madarao is now officially male.
Actually, an omake the author revealed that he intended from the beginning to be gay
Hakubi
Gratuitous English: His frequent referral to Tokine as "honey." When he was Tokiko's partner, he called her "bunny."