Charcoal (木炭) is Koakuma's pet bat.
Charcoal has shot, slick grey fur, with long wings. She also has large, dangerous fangs, willing to anytime pierce though anyone's skin, except her friends/owner.
- Pierce: Charcoal dives in at the speed of light, and bites her enemy's heart.
- Push And Pull: Charcoal wraps her wings around the enemy's neck, and tugs with all her might, choking the enemy.
- The Razor: Charcoal swings in by the enemy, brings out her claws, and flies close to the enemy, goes in a spiral, leaving cuts everywhere.