Binding of Isaac: Rebirth Wiki

Added in Repentance

The Heretic is a boss added in The Binding of Isaac: Repentance that can appear in the Mausoleum Mausoleum.


Phase 1[]

  • During the beginning of the fight, 5 Exorcist Exorcists, which are shielded and invulnerable, summon The Heretic from a large pentagram, after which they turn into Fanatic Fanatics.
    • The Heretic is incorporeal until all Fanatics and the Pacer Pacers or Gusher Gushers they turn into are dead, similar to The Haunt The Haunt's first phase.
    • While incorporeal, The Heretic can still do contact damage.

Phase 2[]

  • Lobs 7 projectiles that, after landing, burst into 6 fires that spread out in a radial pattern. The landing position of each projectile is marked on the ground.
    • The Heretic then follows up by launching itself towards Isaac, creating a radial burst of 8 lines of fire where it lands. It spends a short time readjusting its dislocated jaw before continuing to attack.
  • The arena of the Heretic always spawns a number of unlit Fire Places. The Heretic can light up 5-6 of them before firing a purple Brimstone Brimstone laser that connects all of the lit fires. The order the Heretic lights each fire indicates what order the laser travels.
    • These can be extinguished with an explosion, preventing Brimstone lasers from reaching the deactivated Fire Place.
  • Dashes off-screen and turns invisible before charging in again, predicting Isaac's movements and attempting to bite down on where Isaac is moving, doing a full heart of damage if the attack connects. It chains this attack a total of 4 times, each time from alternating sides of the room.
    • The Heretic occasionally does not finish the fourth charge, instead fading away and quickly charging in one final time from the other side of the screen.
  • Upon death, the Heretic's fiery eye drops down and sends out lines of fire in the cardinal directions.



  • When not fought as a main boss, such as in a Boss Challenge room or a degraded boss, it will not be preceded by Fanatics and have no first phase.
    • The Heretic also cannot perform its Brimstone Brimstone attack outside of its regular boss room as there will be no unlit Fire Places.
  • The Heretic can be instantly killed with Vade Retro Vade Retro if it is at 50% health or below.


  • The Heretic originates from a Reddit post by NotYourSaggitarius in 2015, as a versus screen mockup. The boss was later incorporated into the Antibirth mod.
  • It appears to be a resurrected variation of The Haunt or The Forsaken The Forsaken.
  • The only time The Heretic's empty right eye lights up is during its Brimstone Brimstone attack.
  • The Exorcists that appear during the beginning of the fight to summon The Heretic are found nowhere else in the Mausoleum Mausoleum, unlike in Antibirth, where they were a regularly appearing Monster.
    • As of Repentance version 4.0.3, the Exorcists exist in the bestiary, but even using a Chaos Card Chaos Card to kill them will not add them to the bestiary, leaving it currently impossible to complete.