Alternative Character Interpretation: Was the neglect and abuse Amys family directed at her the cause or the result of Amys psychopathy? The fact that all flashbacks of her childhood are shown before the reveal that Amy is a deranged serial killer set on being Malphass vessel make it even more ambiguous.
Complete Monster: Amy Hughes, a counselor at Camp Stillwater, is actually a remorseless psychopath. As a child, they murdered their parents and brother by purposefully closing a fire place flue, allowing the carbon monoxide to suffocate them to death. Becoming enamored by Malphas, they manipulate their friend Margot Tate into accompanying them to a party, and personally drops the latter to her death in order to acquire her position. With their goal being to resurrect Malphas by becoming his vessel, they conspire against the counselors, killing them in gruesome fashion and using their corpses to create a pentagram. Examples of these murders include decapitation, drowning, and a bear trap to the head. Allowing Malphas to re-enter into then after he was exorcised, they hack the owner of the camp, Deb Carpenter, and Margot's friend to death when she was trying to warn the former. Realizing they couldn't leave the camp due to Holyoke implanting a fragment of his soul into Jessie Tyler, they reanimate the corpses of the slain counselors, and sends them to kill her. In their rampage, they also kill a few police officers that were called to investigate and mimics one of their voices as a ploy to lure Jessie out from hiding. Despite a tragic backstory, Amy proves to be a manipulative sadist who successfully hid their sinister designs with a smile.
Moral Event Horizon: Alan crosses this when he injects his pregnant wife, Lydia, with the zombie serum. If that wasn't enough, he injects the zoo animals with it to build an army, and then zombifies William.