西崎 秋斗

The tiger-class, Youma form of Akito. In this form, he is more powerful than Shishihara and faster than Rin. 

Unknown to him, he is the last surviving member of the Nishizaki clan, so the tiger-class youma flows within his blood. It is the reason why he wasn't infected by the lion-class or snake-class youma virus.