A strict disciplinarian who also runs a dojo primarily focused on kenpo martial arts, Makoto's father is a man of tradition. He believes that absolute respect from his family is crucial. However, when his eldest child, Sakura, eloped to avoid an arranged marriage he had set up to preserve the dojo, he became deeply dissatisfied with rebellion. To prevent his other children from following in her footsteps, he took extreme measures to ensure their obedience, especially with Makoto, his only son and heir to the dojo. Masumi subjected Makoto to intense training, rarely allowing him to leave the house.
Eventually, things settled down, but not for long. When Makoto approached him with a proposal, instead of granting him freedom, Masumi challenged him to disguise himself during his final years of high school to prove his seriousness. Masumi frequently sends spies to monitor whether Makoto is keeping his word, though he eventually calls them off before issuing another challenge to Makoto.
While he is stricter with most of his children, Masumi has a softer side, particularly towards his wife and second eldest child, Tsubaki. This is likely because his wife can match him in ferocity, and Tsubaki is the most obedient of his children. He especially enjoys eating his wife's homemade caramel flan, which he consumes five times a day.
