Makihisa is the one responsible for much of the events of the series, due to kidnapping Shiki Nanaya from his family, hiring Kouma Kishima to slaughter the rest of the Nanaya family, his brutal treatment of Kohaku, and his strict training of Akiha. Like all of the Tohno family, he possesses demonic blood, which cause him bipolar disorder along with schizophrenia. Although his face was never clearly shown, in the manga, it was evident that, during the massacre of the Nanaya family, he had similar abilities to that of SHIKI Tohno, as he could solidify blood from inflicted wounds and use it as a sword-like weapon.
Before the events of Tsukihime, he was seemingly murdered by SHIKI. It is his passing, along with the awakening of Roa/SHIKI, that begins these events. During the course of the story, much is revealed as to why Shiki was brought into the Tohno family and how Hisui and Kohaku came to be at the Tohno Mansion.