The Binding of Isaac Wiki
Advertisement
The Binding of Isaac Wiki

Xxx form2.png Isaac Rebirth.png

This article refers Isaac as a boss. For the character, see Isaac.
For other uses, see Isaac (disambiguation).

Isaac (アイザック Aizakku) is a boss added with the Wrath of the Lamb DLC for the original game, and also appears in the Rebirth DLC. He is the game's main character as the final, fixed boss of The Cathedral.

Behavior

Phase 1

1st phase.

Isaac will appear lying down in the center of the room, crying on the floor. He shoots 12 high-velocity tears in a radial burst and will retaliate with streams of tears when hit.

Phase 2

2nd phase.

At 66% of his health, a light will shine on Isaac, and he jumps from the ground. Isaac will then start shooting 4 large purple tears, which home slightly, in all directions. He will still retaliate with some tears when hit.

Phase 3

3rd phase.

Triggered near 33% of Isaac's health. Isaac will grow angel wings, smile, and start floating. White beams will be randomly shot down from the sky (Similar to Crack The Sky and White Pony), Angel Babies will start spawning frequently (up to a maximum of 6), and the same homing projectiles from before will be shot in six directions at the same time. At this point, Isaac will no longer retaliate with tears when hit.

Champion Variants

Eternal

Eternal Isaac acts similarly to normal one. But this time he will randomly teleport himself around the room, making it harder to hit him, he sometimes even teleports himself right onto the player. Note that he slowly regenerates HP during Phase 1.

Notes

  • Using The Bible during or after the fight will instantly kill the player (Similar to ??? and Satan) unless they have The Wafer item, which will deal 1/2 heart damage instead.
  • Using items with a high fire rate (such as Technology 2) is dangerous in this fight, as Isaac will retaliate with a very large amount of tears upon being hit, unless the player have Mom's Contacts. This also applies to effects which apply damage rapidly, such as Mom's Knife.
  • Applying slow effects such as Little Gish or Spider Bite to Isaac will not affect the speed of his homing tears, but will slow all normal tears.
  • Activating Mom's Bra or triggering the special effect of Mom's Contacts will prevent Isaac from spawning enemies or attacking at all—including when damaged—for the duration of the effect.
  • Isaac cannot be damaged by the Crack The Sky light beams, or by his own. However, any Angelic Babies in the fight can take a small amount of damage from his light beams.
  • It is possible to reduce Isaac to 0 health. If Isaac is on 0 hp, the wings and light will disappear, and Isaac will resume crying on the floor. No projectiles/beams of light will be used (just like when ??? (boss) is reduced to 0 hp). However, any angels spawned from the previous phase will still survive, and will continue to attack the player.

Trivia

  • The third form is referenced in the Wrath of the Lamb DLC's trailer, which showed Isaac sprouting wings.
  • From both the original game and Rebirth, in phase 1, Isaac makes the same weeping noises as the Mulligan.
  • When Isaac was first added in the initial release of Wrath of the Lamb, his third form only consisted of the rays of light, except with a tremendous rate of firing.
  • From the original game, the picture of Isaac on Isaac's Last Will is identical to that of the Mulligan, but without the bloated head.

Bugs

  • If the player uses The Hourglass, Isaac will fire blood tears instead of the usual blue tears and purple homing tears.
  • From the original game, if the player is killed by the light beams in the final stage of the battle, the Last Will will display a picture of War.

Videos

Bosses
Chapter 1
Dukeofflies full.png
The Duke of Flies
Gemini full.png
Gemini
260x185-400px-Monstro.svg.png
Monstro
Larryjr full.png
Larry Jr.
287x265-Steven Fullsize.png
Steven
220x287-Isaac Vs famine edited- noobletk.png
Famine
260x200-400px-Widow3.png
WidowDLC.png
Pin clean.png
PinDLC.png
Chapter 2
Fistula.png
Fistula
Gurdy full.png
Gurdy
Peep Full.png
Peep
Chub.png
Chub
Chad full.png
C.H.A.D.
BC Pestilence.png
Pestilence
The Husk.png
The HuskDLC.png
260x220-The Hollow2.png
The HollowDLC.png
Chapter 3
285x230-MonstroII full.png
Monstro II
Loki full.png
Loki
250x250-400px-Mom.png
Mom
Gish full.png
Gish
BC War.png
War
Mask of Infamy.png
Mask of InfamyDLC.png
Chapter 4
Scolex full.png
Scolex
Blastocyst full.png
Blastocyst
Moms Heart Full.png
Mom's Heart
250x250-ITLIVEScutout.png
It Lives
VSDeath.png
Death
250x200-Teratoma..png
TeratomaDLC.png
Lokii cutout.png
LokiiDLC.png
BC Conquest.png
ConquestDLC.png
Chapter 5
Satan Full.png
Satan


Bc isaac.png
IsaacDLC.png
Chapter 6
BC xxx.png
???DLC.png
Any Chapters
TheFallen Full.png
The Fallen*
230x200-Headless Horseman.png
Headless Horseman*
Gurdjr.png
Gurdy Jr.*DLC.png
Blighted ovum.png
Blighted Ovum*DLC.png
Carrionqueen.png
The Carrion Queen*DLC.png
The Wretched.png
The Wretched*DLC.png
VS DaddyLonglegs.png
Daddy Long Legs*DLC.png
Bc Bloat.png
The Bloat*DLC.png
200x300-400px-Triachnid boss portrait.png
Triachnid*DLC.png
Advertisement