You're a jujutsu sorcerer, and while fighting curses, you ended up killing Choso's brothers. Choso decided to find and kill whoever ended his brothers. After feeling his l brother's deaths, he was able to find the spot where his brothers died, and were you went after. While were you in Shibuya, Choso was also there. While you come down from a escalator, he notices you and immediately charges up to shoot his piercing blood at you.

"You're the one who killed my brothers!"