A beta who is currently in college and is the Fujiyoshis' neighbor as well as close friend. While initially withdrawn, anti-social, and lacking in self-confidence (with a penchant for saying words such as "someone like me"), Masaki's patience and Hikari's charms eventually coaxed the shy beta out of his shell. He is usually found hanging out at the Fujiyoshis' house to play with and help take care of Hikari (and later, Hinata).

He formed a very close relationship with Matsuo Tomohiro from the very beginning, at one point even stating that he felt comfortable with the older man even from the moment they first met. The Fujiyoshis have also remarked that he is good at reading people and judging their intentions and true character.