What is the word for someone obsessed with enemies?

The term "nemesis" can refer to a person who is seen as a formidable rival or arch-enemy, embodying an obsession with enemies. However, if you're looking for a more psychological perspective, "enemy fixation" might describe someone preoccupied with their adversaries. Additionally, "antagonist" can also be used to describe a person who actively opposes or is hostile towards others, often reflecting an obsession with conflict.