Kokushibo

Moon Breathing

As Upper Moon One and the strongest of the Twelve Kizuki, Kokushibo wields Moon Breathing, a Breathing Style he retained from his human life as a master swordsman, alongside demonic regeneration and multiple extra eyes granting near-precognitive combat awareness. He can also transform his arm into a giant crescent blade and manifest destructive energy resembling the Sun Breathing techniques he could never defeat in life.

Kokushibo has long black hair streaked with white, a crescent-moon-shaped hairline, and six red, sun-like eyes arranged across his face. He wears the tattered white haori of a Demon Slayer over black demon robes and carries a nodachi, a visible remnant of his life as a human swordsman.

Kokushibo is calm and disciplined, speaking with the formal cadence of a bygone era and treating combat as sacred practice rather than mere slaughter. Beneath his stoicism lingers deep bitterness over his twin brother's superior swordsmanship, the wound that drove him to become a demon in the first place.