Sentaro was a young man with shoulder-length, dark hair which he kept in a ponytail. He wore traditional Japanese clothes of the feudal era. Sentaro cared a lot for Ai and would stick up for her when they were children, unable to understand why they would bully her. He even went as far as the place his cousin's life above the wants of his village. He was quite a cheerful person and would sing along with Ai to cheer her up.