Satan

Satan is the boss of Sheol, and the final boss of Ending 12. • Judas - Defeat Satan. • The Negative - Defeat Satan 5 times. • Mom's Knife - Defeat Satan as Isaac. • Guardian Angel - Defeat Satan as Magdalene. • A Bag of Bombs - Defeat Satan as Cain. • Judas' Tongue - Defeat Satan as Judas. • Forget Me Now - Defeat Satan as ???. • The Razor - Defeat Satan as Eve. • Blood Rights - Defeat Satan as Samson. • Daemon's Tail - Defeat Satan as Azazel. • Broken Ankh - Defeat Satan as Lazarus. • Book of Secrets - Defeat Satan as Eden. • The Mind - Defeat Satan as The Lost. • Serpent's Kiss - Defeat Satan as Lilith. • Keeper holds Store Key - Defeat Satan as Keeper. • Locust of Pestilence - Defeat Satan as Apollyon. • Pointy Rib - Defeat Satan as The Forgotten. • Urn of Souls - Defeat Satan as Bethany. • Red Stew - Defeat Satan as Jacob and Esau. • Godhead - Earn all 5 / 9 / 10 / 12 Completion Marks on Hard mode as The Lost. • Mom's Lock - Defeat Isaac, ???, Satan, and The Lamb as Tainted Isaac. • Holy Crown - Defeat Isaac, ???, Satan, and The Lamb as Tainted Magdalene. • Gilded Key - Defeat Isaac, ???, Satan, and The Lamb as Tainted Cain. • Your Soul - Defeat Isaac, ???, Satan, and The Lamb as Tainted Judas. • Dingle Berry - Defeat Isaac, ???, Satan, and The Lamb as Tainted ???. • Strange Key - Defeat Isaac, ???, Satan, and The Lamb as Tainted Eve. • Temporary Tattoo - Defeat Isaac, ???, Satan, and The Lamb as Tainted Samson. • Wicked Crown - Defeat Isaac, ???, Satan, and The Lamb as Tainted Azazel. • Torn Pocket - Defeat Isaac, ???, Satan, and The Lamb as Tainted Lazarus. • Nuh Uh! - Defeat Isaac, ???, Satan, and The Lamb as Tainted Eden. • Kid's Drawing - Defeat Isaac, ???, Satan, and The Lamb as Tainted Lost. • The Twins - Defeat Isaac, ???, Satan, and The Lamb as Tainted Lilith. • Keeper's Bargain - Defeat Isaac, ???, Satan, and The Lamb as Tainted Keeper. • Cricket Leg - Defeat Isaac, ???, Satan, and The Lamb as Tainted Apollyon. • Polished Bone - Defeat Isaac, ???, Satan, and The Lamb as Tainted Forgotten. • Expansion Pack - Defeat Isaac, ???, Satan, and The Lamb as Tainted Bethany. • RC Remote - Defeat Isaac, ???, Satan, and The Lamb as Tainted Jacob.

• Every time Satan is defeated, the current savefile's image changes until The Negative is unlocked.
• Defeating Satan for the 1st time will unlock Champion versions of Bosses.
• Using the The Bible or XV - The Devil? on Satan will instantly kill Isaac.
• On the third wave, Pyromaniac and/or Host Hat will be extremely useful, as Kamikaze Leeches and stomping (which is considered as an explosion) will not hurt Isaac.
• Stomps are no longer considered explosions and cannot have their damage negated.
• Unlike in the original Binding of Isaac, Satan's feet don't cause damage on contact for the short time they rest on the ground after a stomp, providing a window of opportunity to deal significant damage with orbitals such as Sacrificial Dagger, or activate other contact effects like Midas' Touch.

• Satan appeared in the Halloween Update for the original The Binding of Isaac.
• Satan's pose as a statue and during the VS Screen is a nod to the demon Baphomet, who is usually portrayed in a similar pose.
• Satan, in mythology, began as a fallen angel but evolved over time into a greater evil. This may be the reason The Fallen spawns at the start of the fight.
• The demonic speech Satan shouts at the start of his first phase reuses one of Mom's voice lines, shouting "Isaac!" in reverse with heavy distortion.
• The music that plays during this battle is titled Hericide. He​ricide is a combination of the latin word herus (or erus), meaning master or lord, and the suffix -cide, denoting the act of killing.
• This music also plays during the battle against Mega Satan.
• This music also plays during the nightmare wave of Greed Mode, for unlocking the floor's Devil Room or Angel Room.