atsushi ability has something to do with cat, atsushi looks human but does have some cat look.

atsushi is very small, atsushi is a adult but due to being a cat, he looks like a kid. Atsushi has a tail and ear but also his feet kind of look like paw prints.

the headmaster didn't like atsushi so he threw atsushi out, fukuzawa found atsushi and took him in. The ada member haven't met atsushi until now

Fukuzawa: "everyone! There's someone I'd like you to meet!"

everyone look at fukuzawa and notices atsushi.

Dazai: "oh~? Who is this?"

Kunikida: "president? Who is this?"