Breezepelt was a WindClan warrior. Before his birth, his father Crowfeather had two separate forbidden relationships with the she-cats, Feathertail, warrior of Riverclan and Leafpool, Medicine cat of Thunderclan. Due to Feathertail dying and Leafpool choosing loyalty to her Clan, Crowfeather had to reluctantly return to a suspicious WindClan. To prove his loyalty, he became mates with an ageing Nightcloud, who feared she would never have kits. However, Crowfeather couldn't get over his previous mates, never able to truly love Nightcloud, even if he did care about her.
The family of three were very dysfunctional, with Crowfeather strict and distant, Nightcloud clingy and jealous, and Breezepelt himself spoiled and disrespectful. They would constantly bicker, well into Breezepelt's adulthood. He'd also insult and disobey everyone outside of his family, even those who saved his life. As an apprentice, he provoked an unnecessary battle with an innocent RiverClan patrol and led a group of apprentices to fight dogs, going against their mentors' orders. However, Nightcloud would only end up encouraging her son's bad behaviour, telling him that his father secretly hated him, when he actually didn't.
Unknown to Breezepelt, it turned out Crowfeather's former mate, Leafpool had been pregnant when she broke up with his father, so he had half-siblings within ThunderClan: Hollyleaf, Lionblaze and Jayfeather. Finding out the news before him, his half-sister Hollyleaf, who was having a mental breakdown due to it, told the secret at a Gathering. He was enraged by this, knowing it was the truth, despite Crowfeather denying it. After this, Breezepelt began hating his half-siblings.
At the same time, the spirits of the Dark Forest had begun to target vulnerable living cats. Recruiting them as trainees, giving them brutal training in their dreams. Promising to make them stronger warriors for their Clan and help them seek revenge. Breezepelt was among them, becoming one of their most loyal followers. The Dark Forest cats would purposely overexaggerate Crowfeather's treatment of Breezepelt, convincing him he needed to avenge himself. Instead of going after Crowfeather, however, Breezepelt decided to go after Leafpool's litter, thinking they should never have been born.
His first act of revenge, was stalking two ThunderClan cats; the blind Medicine cat Jayfeather and the pregnant queen Poppyfrost. He found them at the Moonpool, a sacred place of Starclan. While Jayfeather was attempting to calm a distressed Poppyfrost, Breezepelt showed himself. With the help of a Dark Forest spirit named Brokenstar, Breezepelt beats up his blind brother while Poppyfrost was forced to watch. He was torn between deciding on whether he should kill them both, or just kill Poppyfrost and frame the murder on Jayfeather. However before he could do this, Starclan appear, chasing Breezepelt and Brokenstar away.
A while later, Lionblaze and Breezepelt end up getting into a border fight for prey while Nightcloud and Crowfeather watch, while Leafpool soon arrives, breaking it up. Leafpool begs to know how Crowfeather could just watch his sons fight, despite Nightcloud angrily retorting that he only has one son. Still wanting to fight, Breezepelt attacks Leafpool, with Crowfeather quickly throwing him off of her. Crowfeather stands over a bleeding Leafpool laying on the floor, reminding her she choose her Clan. In a fit of jealousy, Nightcloud drags Crowfeather towards her, digging her claws in. Her mate breaks away from her grasp, hissing. To this, Breezepelt rushes between them, telling his father to leave his mother alone. Eventually, the two families reluctantly go their separate ways.
The Dark Forest training turns out to be deadly, when a Windclan trainee, Antpelt dies from his wounds. Breezepelt covers up the death and orders the trainees' silence, as Antpelt's ghost will live on through their dreams. Soon though, Antpelt is ordered to fight Ivypool, a living Thunderclan cat, to the death. When Ivypool finally wins, Antpelt dies a second time, which causes the spirit to fade out of existence. Breezepelt promises Ivypool she would pay for permanently killing off his old friend.
Finally, the Dark Forest announce their true goal: to appear in the physical world and lead a genocide against the four Clans with the aid of the living trainees. In response, Beetlewhisker, a Riverclan trainee, threatens to leave. However, Brokenstar makes an example of him, snapping his neck and throwing the limp body towards the other trainees. When questioned if they will leave the Dark Forest too, out of shock, the Trainees reluctantly say no. Seemingly unfazed by Beetlewhisker's death, Breezepelt confidently assures his loyalty, claiming he has no reason to leave "the strongest Clan".
When the battle between the Clans, Starclan and the Dark Forest comes, most of the trainees immediately go into hiding to avoid fighting anyone. Unlike them, Breezepelt eagerly fights on the Dark Forest's side. The only other one to do this is Redwillow, who's instantly executed when his treachery exposed. There, Breezepelt joins an assault on WindClan, attacking his own clanmates, including Crowfeather. Ivypool, who'd been a spy for Thunderclan the entire time, attempts to convince all her fellow trainees to fight for StarClan and the Clans. She knocks Breezepelt off of his Clanmate, shouting for him to stop. Baffled by this, Breezepelt asks her if she's crazy. Where Ivypool is suddenly discovered to be a traitor by Thistleclaw, a Dark Forest tom, Breezepelt leaves her for dead.
Continuing to fight the Four Clans, Breezepelt next moves onto ThunderClan. Finding Lionblaze, he attacks and overpowers him, due the element of surprise. He pins Lionblaze down, gloating he's not as strong as he thought he'd been. Celebrating Hollyleaf's death for a moment, who'd been killed earlier while saving Ivypool, Breezepelt is about to kill Lionblaze. Just in time, Crowfeather saves his estranged son, shoving Breezepelt off of him. Enraged, Breezepelt snarls he always knew his father hated him. Crowfeather denies the accusation, stating that was just what Nightcloud told him. He then states that it is too late for Breezepelt, as his son is already a grown warrior and has been making his own decisions for a long time, finally chasing Breezepelt away.
After the battle, the four leaders hold a special meeting to decide the fate of the surviving former trainees. While everyone else, who never actually fought for Dark Forest, deeply regrets their actions and beg for forgiveness, Breezepelt is shown to be smug and silently defiant, thinking he's done nothing wrong. However, due to the weakened Clans needing all their warriors and the others trainees' regret, they must all be forgiven, including Breezepelt.
Afterwards, Breezepelt is on slightly better terms with Crowfeather and makes no further attempts to kill Lionblaze or Jayfeather. He becomes mates with Heathertail, having four daughters together. His relationship with his mate or kits is unclear. He retains much of his vicious attitude and is more aggressive than his Clanmates, often making accusations at Gatherings. When many Shadowclan members defeated to a rouge group, the Kin, Breezepelt claimed they couldn't be trusted. This included demanding the exile of two probated Shadowclan cats, including a pregnant one.