The Heretics are an antagonistic faction in Outlast 2 that are led by the lustful Val. They are in opposition with the Testament of the New Ezekiel, as they believe the Antichrist should be birthed, a complete polarization of the Testament's views. They predominantly live within a mining site somewhere along the outskirts of the Temple Gate.
The Heretics are first seen kidnapping Lynn Langermann and attacking her husband Blake right after she escapes from the Testament's clutches. For most of the game, the Heretics and Lynn are in the mines, preparing for the birth of "the Antichrist".
While Blake travels across the river by raft to reach the mines, the Heretics begin to stalk him and assault him by hurling rocks at him in an attempt to halt his arrival to the mines.
Once Blake reaches the mines, he is constantly hunted and attacked by the Heretics both on ground level and within them, until finally stumbling across Lynn amongst a graphic blood orgy where he is sexually assaulted by Val. The orgy is interrupted by attacking Testament followers, however, who begin to slaughter the Heretics present in the mines . Despite the Testament winning the civil war and destroying the Heretics, their goals are ultimately accomplished as Lynn delivers the baby, which leads to the Testament wiping itself out and leaving Temple Gate empty.
In most, if not all instances where the Heretics are encountered, they are shown to be completely insane to the point of being almost animalistic. They persistently pursue Blake in large numbers throughout the mines while maniacally screaming, growling and chanting incoherently. Some Heretics also seem to communicate with each other in broken English. Despite their feral behavior, they are all shown to be completely loyal to their leader, Val.
Perhaps the most notable abilities the Heretics share among each other is their agility; being able to leap across crevices effortlessly and dropping down from large heights unharmed, to which they use to their advantage to perform surprise attacks on Blake, making them extremely dangerous to anyone. Much like the Testament followers, they are very capable of carrying out unspeakable atrocities (e.g. mutilating and flaying their victims and stringing up their remains, as well as burning people alive and dumping their bodies into the river), further proving that they are no better than their rivals. The Heretics also seem to engage in heavy sexual activities as seen during their orgy ritual.
All of the Heretics appear to lack any clothing except for strange masks made out of twigs and mud with blood markings painted on them, which obscure most of their facial features. Their bodies are coated in mud and blood, the latter most likely being their own or their victims'.