Kosei is a young man with short brown hair, spiked up at odd angles on his head. His eyes are oval-shaped, and as are his large pupils.
His hero costume consists of a simple, light-colored jacket, with matching pants, a dark shirt underneath, and he wears large boots with cylindrical shapes on the soles.
Kosei is a very enthusiastic and competitive individual who tries to hold himself to a high standard as he makes an effort to avoid descending to the level of his rivals.
However, Kosei was not above taunting Katsuki Bakugo himself after stopping the Class 1-A student with his Quirk. Similarly to Neito Monoma, Kosei has no problem settling for less rather than aiming for the top.
He seems to have a subtle yet lecherous side of him, as shown when he got captured and he was mostly thinking about how Tsuyu Asui's tongue was wrapped around him.
Solid Air (
- Air Prison (エアプリズン Ea Purizun?): Kosei refined his Quirk since the Forest Training Camp Arc, and is able to send out squares of air, and shape them into a box to imprison his opponent. The fact that Koji Koda was imprisoned there for a while and Jurota Shishida had problems containing Koji's strength shows that these air prisons are much more durable than solid air he has shown previously. He displays this ability in the first round of the Class 1-A vs Class 1-B training event.