Yellowfang, a devoted ShadowClan medicine cat, gives birth to three kittens, despite it being against the rules of being a medicine cat to do so. One of her two daughters died very shortly after birth, and the other one was stillborn. However, one kitten did survive. A genetic problem causes her one remaining kit to have an upward bend in his tail. Yellowfang calls him Brokenkit, not because of his tail, but because of her sorrow over her deceased daughters. She takes him outside, and when Brokenkit is able to see and hear, he attempts to play with the other kits, Deerkit, Runningkit, and Tanglekit, but they bully him and call him, badger stinky, kittypet and a rogue, which are insults to warriors and cats of other ranks. Yellowfang defends him, and takes him to the medicine den so she could teach Brokenkit different herbs. Brokenkit didn't like being in the den, and instead wanted to become a warrior.
Brokenpaw is mentioned as a new ShadowClan apprentice at the gathering by Leopardfoot, a Thunderclan warrior. She also says that he got in a fight with two RiverClan apprentices, breaking a truce until Oakheart, a RiverClan warrior breaks it up. Raggedstar, Brokenpaw's father, was said to be furious.
Into the Wild
Brokenstar is first seen at Firepaw's first gathering. The first thing that Firepaw and greypaw notice is that is ShadowClan apprentices are very small, which is later revealed that Brokenstar trains them at only three moons when they are supposed to be six moons old to start training, and makes them Warriors at five. When the gathering begins he says that he needs more food and water and territory for starving kits and he says that WindClan failed to understand and that he had to drive them out so that he and his clan could have their territory. RiverClan's leader, Crookedstar, says that he will share his territory with ShadowClan, but ThunderClan's leader, Bluestar, says that she will think about it. Near the end of the gathering, he mentions Yellowfang and that he exiled her and that she tried to murder kits, it is later revealed that he killed the kits, he tells the clans not to take Yellowfang in. Brokenstar later sends Clawface, a ShadowClan warrior, to kidnap Frostfur's kits. When he does, he kills Spottedleaf, the Thunderclan medicine den, and ThunderClan suspects Yellowfang of the murder because she leaves ThunderClan to go save the kits to prove her loyalty to ThunderClan. Yellowfang later raids ShadowClan with Firepaw, Greypaw, a ThunderClan patrol, and some ShadowClan elders that have been kicked out earlier. They win the battle, and drive Brokenstar and his allies out of ShadowClan.
Fire and Ice
After being driven out of Shadowclan, Brokenstar and his team of rogues decide to raid the ThunderClan camp. They attack with Fireheart being the only warrior there. Later, one of his clanmates is killed and the rest of the rogues are driven out of camp, and Yellowfang blinds him. Then, Brokenstar is taken into custody as a prisoner of ThunderClan.
Forest of Secrets
Brokenstar, now called Brokentail, is still a prisoner of Thunderclan, but he seems to get along with Tigerclaw very well, because every night, Fireheart catches them talking to each other as if they were friends. Then, the other clans find out that Brokentail is still alive, and WindClan and Shadowclan launch an attack on Thunderclan to kill Brokentail, but Thunderclan fights back, saving Brokentail's life. Later, Brokentail's old team of rogues attack the camp, and Brokentail attacks the cats guarding him as Tigerclaw aids the rogues in the attack. Yellowfang then feeds Brokentail deathberries, Which kills him, and all the rogues retreat and Tigerclaw is exiled from ThunderClan.
The Rise of Scourge
Brokenstar appears in the manga with two other cats, they were fighting with one rouge before Scourge steps in, telling Brokenstar and his warriors to leave. Brokenstar laughs along with the two warriors and begins to taunt Scourge for his small size. One Shadowclan warrior then attacks Scourge, but the Bloodclan leader dodges and kills the warrior instead with a slash to the throat.
Brokenstar and the other warrior then leave Bloodclan territory. Scourge then states a rule that cats must ask before eating prey.
This is the only time Brokenstar is ever seen in the manga.
Omen of the Stars
Brokenstar appears as one of the leaders of the Dark Forest cats, actively corrupting and training currently alive cats to be warriors for the Dark Forest so they can assist in their coming attack on the forest.
Brokenstar is one of the darkest villains in the Warriors series. Incredibly brutal, cruel and sadistic, Brokenstar made it a habit of his own to murder and terrorize other cats all just for power and pleasure.
As a leader, Brokenstar was a selfish and violent. He was constantly attacking other Clans in order to take their land and drive them out. He was also a cruel and terrorizing leader, making up harsh rules for his cats to live in. He did not mind murdering other cats to achieve what he wanted. He was also very aggressive and battle-hungry, as he intentionally tried to provoke a war with Windclan and later drove them out when he became leader to take their territory.
Brokenstar is probably best known for being violent. As an apprentice, he has asked multiple times to change his mentor because he was not "teaching him enough battle moves" and because he was "too soft". As the deputy of his clan, Brokenstar murdered his own father (who was leader at that time), in order to become leader himself. He then begun to harshly train 4 months old kits (kits become apprentices at 6 months old) strict battle moves and send them into battle. He also exiled elders of his clan and left them to fend for themselves because they were "useless" to the clan.
Brokenstar has shown to have absolutely no respect for other cats and clans, insulting any cat he sees. He has also been shown to be very callous towards his clan and other cats, only caring about himself. He was arrogant, selfish and self-centered.
Brokenstar was also a hypocrite, as he often criticized those who broke the warrior code, but constantly broke it himself in order to get what he wanted.