ThunderClan – the main Clan in the series and receives most of the attention. ThunderClan warriors are brave, strong, and fierce, but also playful and friendly. Their territory is a vast expanse of forest. They hunt squirrels, birds, mice, and rabbits.
RiverClan – the Clan bordering ThunderClan to the left. They’re sleek and well-fed with fur naturally resistant to water, enabling them to be talented swimmers. Their territory is a triangular peninsula surrounded on three sides by a swift, flowing river. They mainly feed on fish and water voles.
ShadowClan – It is said the North wind blows over ShadowClan and chills their hearts. They're not evil, just not the nicest of cats. They live in a marshland, and are known for eating whatever they can find - even frogs and lizards.
WindClan – the cats of WindClan are very agile and fast. They're generally friendly and helpful and have a good relationship with ThunderClan. They live on the flat moorland, and hunt mainly rabbits.
StarClan - A beautiful land where the dead cats reside (unless they're evil, in which they go to the Dark Forest). They can walk in the dreams of the living cats and deliver prophecies. They have a very close connection with the medicine cat of each clan.
Kit: A kitten. Each kit's name ends in "kit". (Examples: Snowkit, Hollykit, Leafkit, Lionkit, etc.)
Apprentice: Once a kit is six moons (months) old, they become an apprentice. The "kit" in their name is replaced with "paw" and they are assigned a mentor. (Examples: Hollypaw, Lionpaw, Cinderpaw, Ashpaw, etc.)
Warrior: Once an apprentice has completed training, they receive their full warrior name. The "paw" is replaced with something that fits them, whether it's by looks or personality. (Examples: Hollyleaf, Lionblaze, Fireheart, Graystripe, Bluefur, etc.)
Elder: When a warrior has served a long and full life in the Clan, they retire to the elder's den and finally get some peace and quiet. They're known for being grumpy and always talking about the "old days". Elders do not receive a name change.
Medicine Cat Apprentice: The apprentice of the medicine cat and healer-in-training. They learn the use of each herb and have a close connection with StarClan. There is ONE medicine cat apprentice in each Clan. They are named like a normal apprentice.
Medicine Cat: The healer of the Clan. They fix up the cats using their knowledge of herbs, and often receive prophecies from the warrior ancestors in StarClan. There is ONE medicine cat in each Clan. They are named like a normal warrior.
Deputy: The second-in-command. If the leader dies, they will become the new leader. Deputies must have held warrior status and trained an apprentice. They are named like a normal warrior. There is ONE deputy in each Clan.
Leader: The leader of the Clan and the one who calls the shots. There is ONE leader in each Clan - however, in the first series Bluestar and Firestar were leaders of ThunderClan at different times so keep that in mind. Leaders receive nine lives from StarClan and have the end of their name changed to "star". (Examples: Bluestar, Firestar, Tigerstar, Leopardstar, Crookedstar, etc.)