Main Antagonists:
* Tigerstar: The most infamous villain, a ruthless, power-hungry cat who embodies the series' themes of ambition and betrayal. He appears in multiple books and has several reincarnations.
* Scourge (formerly Tiny): A brutal, vicious leader of BloodClan, a vicious group of cats who terrorize the forest.
* Darktail: A cunning, manipulative rogue cat who tries to take over the Clans.
* Brokenstar (formerly Brokenkit/Brokenpaw): A cruel and tyrannical leader of ShadowClan, who was raised by a terrible mother and turned into a merciless tyrant.
Other Notable Antagonists:
* Hawkfrost: Tigerstar's son, a cunning and ruthless cat who becomes a leader of RiverClan.
* Onestar: A somewhat naive leader of WindClan, who is easily manipulated by other cats.
* Ashfur: A bitter and vengeful cat, obsessed with Squirrelflight.
* Mapleshade: A vengeful spirit, driven mad by grief and betrayal.
* Blackstar: A more complex antagonist, leader of ShadowClan who is driven by paranoia and fear of the outside world.
* Sol: A powerful rogue cat who manipulates the Clans for his own gain.
Let me know if you'd like more information on any of these characters!