He plays percussion and is the leader of Blast usually handling the business partnerships and financial decisions needed for the bands success. His favorite cigarette brand is Black Stones from which the band got their name. He is also a lawyer in training despite his scary appearance clean shaven head many earrings and dark glasses. Hes the big brother figure for Nana Oand sometimes Nobuand acted as Nanas guardian when she arrived in Tokyo. While he harbors some feelings for her he baits Ren to rekindle their love for each other. In the past he shared several ties with Trapnests members. Yasu and Ren grew up in the same orphanage and remained close friends when Yasu was adopted. He dated Reira while in high school and was jealous of Takumis success and influence on her which he later relates as the reasons for their break up. Also hes the oldest member of Blast which Nobu sometimes teases him about by calling him old man. He is in a budding romance with Miu to the surprise of Ren and otherswho were sure he would date Reira again.