Yoshizumi is a researcher dedicated to the study of golems, driven by the goal of conquering death through artificial life. His experiments involve human body parts and zombies in a corrupted pursuit of immortality, earning him the occasional moniker "Rabbi" for his inspiration in traditional golem lore, though his methods resemble Frankenstein-like science.

He has blond hair and orange eyes, and wears red glasses.

His primary objective is to obtain the Corpse Release Spell, or law of shikai, believed to be held by Shito Tachibana's family, to stabilize his golems without constant drug injections. To acquire it, he kidnaps Shito with the intent to trade him to the Xu Fu mafia.

Yoshizumi created three golems: a scrawny, silent girl treated as a failure; a large executioner-type; and his most perfected creation, Phalanx—a limb collection lacking a brain. To complete it, Yoshizumi fuses his own body with Phalanx.

During Shito's captivity, the female golem tends to him with kindness, nursing his health and combing his hair with his mother's comb. Shito grows fond of her, associating her with his mother. Viewing her as defective, Yoshizumu offers her for absorption by Phalanx. Shito intervenes, promising to raise her and teach her to speak, but Yoshizumi's assistant Nogi shoots the golem girl, calling her a monster. It is noted that, as a golem, she never had a soul.

Yoshizumi's work draws the attention of the Akashic Record Reform Committee, whose agent offers to bend rules to aid him.

Fused with Phalanx, Yoshizumi is defeated when Nogi, remorseful, uses a neutralizing agent to poison him, causing his dissolution. Afterward, the female golem is buried by Shito in a human funeral. He implies he named her Inochi, meaning "Life."