Firestar was a leader of ThunderClan in the forest and the lake territories, and prophesied as the "fire to save ThunderClan." He was born to Jake and Nutmeg, and lived as a kittypet named Rusty. He joined ThunderClan as an apprentice, receiving the name of Firepaw, and was mentored by Lionheart and Tigerclaw before being assigned to Bluestar. Fireheart earned his warrior name, and ascended to deputyship after Tigerclaw's banishment. He also mentored Cinderpelt before her injury, his nephew, Cloudtail, and Tigerclaw's son, Brambleclaw. After Bluestar's death, he rose to leader as Firestar appointing Whitestorm as his second-in-command. He later passed the role to Graystripe upon the white deputy's death during the battle against BloodClan, and defeated Scourge. Firestar became mates with Sandstorm, and they went on a journey to rebuild SkyClan. They were successful, and upon their return, had two daughters together: Leafpool and Squirrelflight. He is the most important cat in the series!

RiverClan is known for their skill at swimming. RiverClan cats are also known for their unique skill at scooping fish from the river. The very first leader was Riverstar, who was a loner that met the cats that came from the mountains. At the beginning of The Prophecies Begin arc, RiverClan was led by Crookedstar, with Oakheart as deputy. RiverClan is currently led by Mistystar with Reedwhisker as deputy.

ShadowClan

ShadowClan, the source of many of the darker cats seen in the series, is sometimes referred to as the "dark heart of the forest." ShadowClan cats are known for their ability to walk quietly and avoid detection. They are also known for their willingness to eat frogs, toads, lizards, rats, and crowfood- foods most Clan cats turn their noses up at. Their first leader was Shadowstar. She was one of the cats to make the journey from the mountain to the forest, and she lead the traveling group at one point in time. At the beginning of The Prophecies Begin, ShadowClan was led by Brokenstar, with Blackfoot as deputy. ShadowClan is currently led by Tigerstar, with Cloverfoot as deputy.

ThunderClan

ThunderClan is heavily featured in the books, being the Clan of origin for many of the protagonists of the arcs. ThunderClan cats are known for their skill at stalking prey through forest and undergrowth. The very first leader was Thunderstar, who was the son of the first SkyClan leader, Skystar. He was born in a monster den to a she-cat named Storm, when the monster den collapsed. She had left Skystar's forest after he was overly protective. Thunder was her only surviving kit. At the beginning of The Prophecies Begin, ThunderClan was led by Bluestar, and Redtail was deputy. ThunderClan is now led by Squirrelflight as temporary leader, with Lionblaze as temporary deputy.

WindClan

WindClan, who lived closest to the Moonstone, are cats well versed in Twoleg culture (due to the farm they lived so close to). WindClan Cats are known for their swift paws, which lend ease to catching prey such as rabbits on the open moors of their territory. Their very first leader was Windstar, who was also known as Wind Runner. She and her mate, Gorsestar joined the Early Settlers. Before Windstar became the leader of WindClan, Gray Wing and Shadowstar held the leadership. At the beginning of The Prophecies Begin, WindClan was led by Tallstar, with Deadfoot as deputy. WindClan is now led by Harestar, with Crowfeather as deputy.

SkyClan

SkyClan was the fifth Clan of the forest, and they were introduced in Firestar's Quest. They had to leave the forest a long time ago when their territory was destroyed, which severed their ties with the other Clans. They were known for their ability to jump considerable heights, and they have hard gray pads that help them walk long distances on rough surfaces. Their first leader was Skystar. When the mountain cats arrived at the forest, Clear Sky established a group. He and his group soon became known as the most ruthless, strong, and well-fed cats in the forest. SkyClan is currently led by Leafstar, with Hawkwing as her deputy.

BloodClan

BloodClan is an unofficial Clan. Its only known members are Scourge, Ice, Snake, Bone, Jaggedtooth, and Brick. Boulder, Snipe, Barley, and Violet were known members but left BloodClan. The Clan laws are quite different compared to the official Clans. They do not believe in StarClan. BloodClan does not care for the sick, weak, or elderly and instead throws them out on the borders and makes them fend for themselves. They eat anything they find. The last known leaders were Ice and Snake.

WarriorClan