It is said that his name comes from the fact that Awataguchi Yoshimitsu, who is known as a master tanto (dagger) maker, made only one tachi (long sword) in his lifetime. He is adored by the Toushiro brothers, and they refer to him as their oldest brother "Ichi-nii." He is always kind and has a gentle smile on his face, but sometimes an expression with a hint of sadness appears.
In this game, he is assigned to the Second Team along with Namazuo Toushiro.