Kaede Kayano

For most of the series Kayano keeps her light-green hair in cat-ear pigtails, framed by squared-off bangs above her brows. Her eyes are hazel, and one recurring joke in the class centers on her flat chest, which earns her the codename Forever Flat. Let loose, as glimpsed in an early episode, her styled hair falls to her shoulders.

The green shade turns out to be a dye job. Her true hair is jet black, wavy, and reaches her waist, tied to the identity she buried. When her hidden tentacles feed on her rage, her hazel irises flare red; stripping the tentacles away restores both her calm eyes and her familiar pigtails. Seven years past graduation she has returned to the long black look, gained enough height to nearly match Nagisa, and filled out somewhat.

Within the classroom Kayano reads as gentle, upbeat, and easygoing, most often filling a support role during assassination attempts by sizing up a scene and molding herself to fit it. That softness sits on top of real steel: she is fiercely empathetic and, once invested in something, whether her fondness for sweets or the truth about her sister Aguri, refuses to be shaken loose. She also carries a loud insecurity about her figure and grumbles whenever busty classmates are nearby.

Much of that sunny front was theater. Before she confronted her teacher, only her stubbornness, her knack for adaptation, and her body-image hangup were genuine; the rest was invented, and her sugar cravings may trace back to the tentacles altering her. Once the tentacles came out of her, though, the warm persona she had faked settled in and became truly hers.

Born Akari Yukimura, she is the younger sibling of the teacher Aguri Yukimura and once starred as a celebrated child actress under the stage name Haruna Mase. A break from the spotlight, suggested by her manager, gradually erased public recognition of her, and she slid back into ordinary schoolgirl life. She was close enough to Aguri to tease her about crushes and sharp enough to warn her off her fiance Kotaro Yanagisawa, whose charm she read as a mask over something rotten.

Wandering near the lab her sister assisted, Akari saw an explosion tear through it. Her small frame let her squeeze through the wreckage to Aguri, only to find her bleeding beneath the tentacled creature that would become Korosensei. The being fled, and Akari, grieving, discovered the leftover tentacle cell fluid. She took Aguri's research home, taught herself what the cells were, and mapped out her revenge. Adopting Kaede Kayano, a name borrowed from a one-off role she had played, she forced her way into Class E by wrecking the chairman's prized belongings, injected herself with the cells, and dyed her hair. She latched onto Nagisa as camouflage, restyled his hair into his signature pigtails, and their friendship began.

Across the school year she hid in the background as logistical support, coined the name Korosensei, and even schemed an assassination built entirely around pudding. When she finally struck, unsheathing her tentacles and claiming both love and murderous intent, Nagisa disarmed her bloodlust with a kiss and Korosensei extracted the tentacles. Learning the full story of Aguri's death, she abandoned vengeance and joined the effort to save her teacher. She was later impaled through the chest just as her sister had been, but Korosensei revived her. After the graduation and his death, she resumed acting as Haruna Mase, her Class E parkour feeding her stunt work.