Firestar

Firestar is the main protagonist of the first arc, The Prophecies Begin, and the leader of ThunderClan after Bluestar and before Bramblestar.

He was born as a kittypet named Rusty to the kittypets Nutmeg and Jake alongside his sister Princess and other unknown siblings. Not much of his backstory as a kittypet is known, but eventually he wound up living in a Twoleg nest near the border of ThunderClan forest territory.

Rusty ventured into the forest one day and found out about the Clans. He ended up joining ThunderClan as an apprentice named Firepaw, and became friends with two other apprentices named Graypaw and Ravenpaw. Through a series of events involving the ThunderClan warrior Tigerclaw, Firepaw, soon given his warrior name, Fireheart, fights to uncover the true cause of the ThunderClan deputy, Redtail's death and expose Tigerclaw as a villain. He becomes deputy of ThunderClan after Tigerclaw is exiled for attempted murder of Bluestar.

After the death of Bluestar, indirectly caused by Tigerclaw, now Tigerstar, leader of ShadowClan, Fireheart becomes the leader Firestar. He makes Graystripe deputy and is ultimately responsible for the death of Scourge, the rogue leader of BloodClan that attempted to take over the forest.

Firestar becomes mates with Sandstorm and fathers two she-cats, Leafpool and Squirrelflight. He and Sandstorm travel to reunite SkyClan, and Firestar receives a prophecy from a cat named Skywatcher explaining that three cats, kin of Firestar's kin, will hold the power of the stars in their paws.

He travels with the Clans on the Great Journey to the lake territories and continues to lead ThunderClan as the four Clans settle into their new home.

Firestar becomes a grandfather to Jayfeather, Hollyleaf, and Lionblaze, three cats who are thought to be the kits of Squirrelflight and Brambleclaw, but are actually the kits of Leafpool and Crowfeather, the WindClan warrior who traveled on the journey to the sun-drown place.

Firestar becomes the fourth cat in the prophecy destined to save the Clans from the Dark Forest. He dies shortly after killing Tigerstar's ghost, from either a falling tree or his wounds from the battle (debated between the authors).