Warrior cats

It's a book series by Erin Hunter about feral cats living in the wild. It's generally geared toward younger people, however it's actually a really gruesome series. One cat gets it's stomach ripped open and has to experience the pain of death nine times, another cat gets hit by a car and is disabled for life, a cat gets half it's face ripped off by dogs, three kittens drown in a river while another watches, etc.

It's pretty interesting though, there are four groups of cats that live beside eachother but their always fighting for resources/territory.

The cats also have a pretty unique naming system, when a kitten is born they are named something natural, e.g. a white kitten would be named Snow, Cloud, Mallow. A brown kitten would be named Cedar, Hawk, Adder, Pine, etc.

Kittens have -kit at the end of their name though, resulting in Cedarkit. At 6 months they become an apprentice, earning a -paw at the end of their name, e.g Cedarpaw. Once they are around a year old and complete their training the leader gives apprentices their last name, which is about there skill/personality/looks. Some examples; Cedarclaw - cat who is good at fighting. Cedartail - cat who has good balance. Cedarcloud - a calm/mellow tempered cat. Cedartuft - cat who is unusually or very fluffy.

The only time a warrior would get another name change is if they became a leader, as all leaders names end in star, e.g Cedarstar.