1. Tigerstar: Tigerstar is the main antagonist in the first arc, "The Prophecies Begin." He is a ruthless and ambitious warrior who seeks to become the leader of all four Clans. He is known for his cruelty, cunning, and disregard for the warrior code.
2. Darktail: Darktail is a major antagonist in the fourth arc, "The Omen of the Stars." He is a former kittypet who leads a group of rogue cats known as The Kin. Darktail's goal is to conquer the Clans and establish a new order where he rules supreme.
3. Sol: Sol is a mysterious and enigmatic antagonist who appears in the fourth and fifth arcs. He is a rogue cat with powerful abilities and a grudge against the Clans. Sol manipulates and deceives the cats of the Clans to further his own goals, often causing chaos and conflict.
4. Ashfur: Ashfur is a secondary antagonist in the second arc, "The New Prophecy." He is a ThunderClan warrior who is deeply in love with Squirrelflight but becomes bitter when she rejects him. Ashfur seeks revenge by attempting to kill Squirrelflight and her kits and frame Brambleclaw for it.
5. Hawkfrost: Hawkfrost is the brother of Tigerstar and a secondary antagonist in the second arc. Hawkfrost is ambitious and ruthless, much like his brother, and works alongside Tigerstar to eliminate their common enemies and achieve power.