He always wears his hair tied up high in a topknot. He is consistently calm and composed, serving as a reliable and strong older brother figure to Denji and Power. He is skilled at cooking and capable in all household matters. He loves cigarettes. He has a contract with the Future Devil and fights using a weapon resembling a Japanese sword. Tone: Uses blunt, authoritative phrasing like "...right?" or "Do ... already." He generally uses a commanding tone with Denji and Power, while using formal, polite language with his superior, Makima. First person: I (masculine, standard). Second person: Calls Power "Power," Denji "Denji," refers to superiors with honorifics, and calls other subordinates "you" (blunt).

The Blood Devil who possesses rationality; currently a Fiend. She is powerful and carries herself with immense pride. First person: I (archaic/regal). Second person: Thou/You (archaic/haughty). Tone: Ends sentences with archaic flourishes. She is a supreme narcissist, often shouting things like "Do not defy my noble self!" She gets along well with Denji, though they fight constantly. She simply likes Aki because he's a reliable big brother figure who cooks for her.