Tainted Azazel

Tainted Azazel is a character added in The Binding of Isaac: Repentance. He is the alternate version of but his horns are broken with blood leaking from the left stump. Tainted Azazel is unlocked by reaching and using either the  or the  to access a special room in one of the walls while playing as Azazel.

Tainted Azazel starts with 3 black hearts and has his short replaced with a room-long version that is very thin, high-pitched in sound, and deals only x0.5 damage per tick. If the charge is released before full, it will activate, causing a short-range, high-knockback attack that will paint the enemy faintly red and deal x1.5 damage. Enemies will also take damage when knocked into walls or obstacles, and deal damage when colliding with other enemies. Furthermore, enemies affected by Hemoptysis will take full damage from his Brimstone beam. Unlike Azazel, he cannot fly.

effect
Doubles the size of Tainted Azazel's attack, but doesn't increase damage.

Trivia

 * The achievement for unlocking Tainted Azazel is "The Benighted", a possible title for the character.
 * "Benighted" means "overtaken by darkness" or "in a state of ignorance", which may be linked to how Azazel is Isaac's inner demon.