Satan

Satan is the boss of Sheol, and the final boss of Ending 12.

Behavior[ | ]

The battle against Satan has three distinct phases.

Phase 1[ | ]

The first phase starts with a slight delay after Isaac enters the room:

Satan shouts, and roughly two seconds after Satan's voice dies out, The Fallen spawns at the center, with two Kamikaze Leeches to either side.

Phase 2[ | ]

Once The Fallen is dead, the Devil Room statue at the top of the screen transforms into Satan's first form. He stays near the top of the room moving horizontally and performs the following attacks:

Spits out 2 consecutive spreads of 5 and 4 projectiles towards Isaac. He chains this attack at least twice.
If Isaac is to either side of him, he can:
- Shoot half-rings of 8 projectiles from both his hands towards the left and right sides of the room.
If Isaac is below him, he can:
- Shoot two Brimstone lasers from his hands, that curve towards each other while leaving a gap in the middle.
- Charge up and fires a Brimstone beam from his mouth directly downwards.

If Satan is pushed too far away from the top center of the room, he will rapidly spring back to that position.

Phase 3[ | ]

After depleting his entire second phase health bar and reaching half of his total HP, he flies off-screen and has one attack:

Stomps the ground with both of his feet at Isaac's previous positions, similar to Mom's stomp attack, but with less delay. The stomps come down one after another, and after two stomps, they persist for a moment before both are retracted.
Up to two Kamikaze Leeches continuously spawn during this phase.
- They can be killed by Satan's stomp, but will also deal considerable damage to him.
- There appears to be a maximum amount of Kamikaze Leeches that can be spawned, as they stop appearing if the fight draws out for too long and the Kamikaze Leeches are not killed.

Satan's projectiles and contact damage deal a whole heart of damage.

Once Satan is defeated, remaining Kamikaze Leeches die alongside him.

Gallery[ | ]

Satan in-game.
Satan in his second form.
Satan in his statue form.
Satan as one of Delirium's forms.
Satan in his second form prior to Repentance.

Unlockable Achievements[ | ]

I RULE! - Defeat ??? or The Lamb, defeat Satan as Isaac, and unlock The Negative
Defeat ??? or The Lamb, and defeat Satan as Isaac
Defeat Mega Satan and unlock The Negative.

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.

Notes[ | ]

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.

Trivia[ | ]

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. Hericide 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.

Bugs[ | ]

Bug!	If exactly 600 HP of damage is dealt to Satan, it will completely skip the third phase and spawn the chest, due to how the boss is coded to go to the third phase only if over 600 damage is dealt. The easiest way to do this is to use only familiars to do damage, or to use 6 bombs (without modifications) against Satan's second phase.