- During the beginning of the fight, 5 Exorcists, which are shielded and invulnerable, summon The Heretic from a large pentagram after which they turn into Fanatics.
- 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 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 attack outside of its regular boss room as there will be no unlit Fire Places.
- It appears to be a resurrected variation of The Haunt or The Forsaken.
- The only time The Heretic's empty right eye lights up is during its Brimstone attack.
- The Exorcists that appear during the beginning of the fight to summon The Heretic are found nowhere else in 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 to kill them will not add them to the bestiary, leaving it currently impossible to complete.
|The Binding of Isaac: Rebirth|
|Achievements||Attributes||Bosses||Cards and Runes||Challenges||Chapters|