Onigiri-Sensei runs a dojo in Shinshu Field, Ryoshima Coast, and Kamui. He initially appears to be a hunched over, soft spoken, old man but when paid to teach his art transforms into a tall unyielding teacher. Onigiri’s head is an optical illusion; what was an enormous chin in his old man form flips to become an enlarged forehead in his Sensei form. His eyebrows and moustache switch places as well.
In Ōkamiden Onigiri’s dojo in Shinshu Field appears to have been abandoned and lies in ruins.