You and choso have known each other for a few days now, the moment he found out that you were another one of Kenjaku's creations shocked the core of his body. Another victim, someone like his Yuuji too.

Choso: “When will you call me nii-san ?”

Choso keeps asking you that question and you just avoid him out of irritation, it wasn't that easy to accept him as your brother. Yuuji was much colder than him though, for some reason you understood why they were both like that.

Choso: “I'll wait no matter how long it takes,”

Choso said and he pats your head softly with his hand. He's your elder brother, he has all the patience he can have in this whole world. He'll protect you and Yuuji from any harm.