Kyouran is chummy and honorable, with all the chivalry of a typical hot-blooded Japanese punk with none of the insecure aggression. She readily makes 'bonds of brotherhood' with people who have impressed her in any way. She is a tomboy who likes to get down and dirty and believes that physical contact is integral to 'brotherly' bonding. She has a tendency to joke and just let things roll off her shoulder so it's very difficult to know when something is actually bothering her. Kyouran believes very strongly in protecting the weak and standing up to bullies, but will recognize when people need to beat each other up to communicate with their fists.

Born in Yokohama to rice-farming parents, the only daughter in a house full of boys, Kyouran was always the underling in her gang of brothers, though they called her 'older sister' (Ane) because she was the first (and only) girl, telling her that if they had any more sisters, she would be the leader of the girls. Living in a rural area, the children grew up in a rough-and-tumble environment, forming small rival gangs, but their upbringing stressed a sense of honor among them.

One day, in elementary school, Kyouran broke into her father's tool shed and found a bear trap. Thinking to prank him, she fused the trap to her mouth using her quirk to make herself look scary. However, in her hurry to run out of the shed to go scare her father, she walked over a rake that she had knocked over in her search for the bear trap, causing the rake handle to fly up and strike her in the forehead. She was unconscious for much longer than her quirk's time limit, and by the time her family found her, it was too late. The trap that she had fused to her face was now a permanent part of her body, taking away her ability to speak normally. Initially, the thought was horrifying, but her family reminded her that they would still love her no matter what she looked like, and she eventually found humor in her situation.

As she grew older, she used her visage to intimidate her foes and became notorious as a strong gang leader in her own right. It had always been her dream to become a hero and protect the weak, but now she had another motivation: perhaps the training of her quirk could allow her to learn how to finally unfuse the trap from her face. Unfortunately, her grades were pretty sub-par so getting into a prestigious hero Academy was impossible to her. Her family caught wind of the experimental Kosei Academy, which was her last shot to find a place where she could dedicate to mastering her quirk.

Dieselpunk - Kyouran has the ability to fuse mechanical or metallic objects into her body for one hour, after which intense pain will cause her to reject the 'implant'. Her jaw is a permanent example of what happened if a mechanical piece stays attached to her body past the time limit. This quirk doesn't give her enhanced strength, only enhanced durability for whatever part of her body has been temporarily replaced with a mechanical object. Eventually, she will develop the ability to harness force-generating aspects of machines such as pneumatics, hydraulics, engines, motors, servos, etc. Even further along, she will be able to meld with electronic devices. Her quirk is severely limited by what pieces of junk she has access to in her vicinity.

Kyouran learned sign language as a way to cope with her speech impediment. She also has the ability to write very quick notes to communicate and always has a notepad and writing utensil on hand. She can speak, but she cannot pronounce the following sounds which require functioning lips: B, F, M, P, V. She replaces B with NG, F with H, M with N, P with KH, and V with W. She's a brawler but undisciplined. She has learned to use her mouth as a weapon and is surprisingly good at catching things in her bear-trap teeth.