Fireheart exposed Tigerclaw as the true killer of Redtail. He stops training his apprentice after that and Fireheart now has two apprentices to train while Graystripe was chasing after Silverstream. They joined ThunderClan. Darkstripe found any way to bother Fireheart and make his duties difficult. When they arrived back at WindClan territory, Tallstar has Onewhisker and Deadfoot take the two warriors home.
Firestar is a well-muscled, slender, lithe,massive, tall, battle-scarred ginger tom with a flame-colored pelt, clear, sharp, brilliant emerald eyes, powerful hind legs, a lean, strong shape, a sleek, thick coat, a pale orange belly, powerful shoulders, long, thorn-sharp claws, soft black pads,a long scar on his flank, a long tail, and large ears,one of which is torn. Bluestar allows the kit to stay and names him Cloudkit.
The day Rusty joined the ThunderClan cats, Redtail died in battle after fighting RiverClan, a rival warrior clan.
She tells him how and he changes Lostface's name to Brightheart.
After a Gathering, when all four Clans meet ever full moon, Fireheart and Graystripe snuck off to see Ravenpaw so they could find out more about Redtail's death. He respected the rules of the Warrior Code, but also had the insight to look beyond them in order to properly judge a questionable situation. All three died of smoke inhalation. Cloudpaw was made into a warrior named Cloudtail. Fireheart later discovers his sister, Princess, after visiting the Twolegplace. Leopardstar, the new leader of RiverClan, had been visiting Tigerstar for a while. He later dies of his wounds and goes to StarClan.
He was made an apprentice and renamed Firepaw.
Yellowfang took the position of Medicine Cat for ThunderClan. Bluestar then had Tigerclaw exiled from ThunderClan. Fireheart told her not to go but she didn't listen and she went to see what Tigerclaw wanted because Bluestar was too ill to come. One day, he finally went outside and met his friend, a kitten named Smudge, who warned him about the wild forest cats in the nearby forest.
Then Cinderpaw was hit by a Monster.
Fireheart accidently attacked Silverstream, but didn't leave a scratch because he didn't want to hurt her. Fireheart had enough problems but then he got one more. She was very hostile towards him, despite her obviously being sick and wounded. When Firepaw was one day hunting for his Clan, he ran into the former ShadowClan medicine cat, Yellowfang.
They attacked ThunderClan and Tigerclaw attempted to kill Bluestar, but Fireheart and Graystripe stopped him. Graystripe got her brother, Brackenpaw. Fireheart then suspects Tigerclaw had wanted to kill Bluestar. Fireheart then was given an apprentice named Cinderpaw. The Clan now only had five apprentices; Firepaw, Graypaw, Ravenpaw, Sandpaw and Dustpaw. Brambleclaw and Greystripe, organise cats to make a clans worth of nests at the abandoned twoleg nest. Dustpelt became Ashpaw's mentor and Darkstripe became Fernpaw's mentor. He also makes Thornpaw into a warrior, Thornclaw. After that, Brackenpaw then was made into a warrior. It has been mentioned multiple times by other characters that Firestar bears a very close resemblance to his father Jake. Swiftpaw, Longtail's apprentice, became angry along with Brightpaw and Thornpaw because they didn't become warriors.
Tallstar then joins forces with Firestar to fight TigerClan but they soon find out Tigerstar had brought BloodClan in to the forest to help fight ThunderClan and WindClan. "Firestar, there's a clan's worth of cats just beyond the border asking for you. Yellowfang goes to save the kits. He was first discovered by Spottedleaf of Thunderclan after she received a mysterious prophecy from Starclan during the book Into the Wild.