|“||My quarrel is with you, Squirrelflight...It always has been||„|
Ashfur was born into a wild cat group known as ThunderClan. As a kitten and apprentice, he had a standard upbringing. Close to his family, to the point of hiding his foster brother, Cloudtail illegally getting food from humans. Despite Cloudtail having a separate background as a born Housecat, this wasn't shown to bother Ashpaw. As an adolescent, his mother, Brindleface was killed by the exiled deputy, Tigerstar while trying to lure a pack of dogs to ThunderClan. Ashpaw avenged her by helping to trick the pack leader into falling into a river, causing the rest of the dogs to retreat. Shortly afterwards, he showed his vengeful side again by being the only apprentice to celebrate killing an invader named Bone.
As a grown cat, Ashfur was an average and respected warrior. He became somewhat friends with Brambleclaw, even though the latter was the son of Tigerstar, the killer of Ashfur's mother. Brambleclaw and an apprentice, Squirrelpaw, would later go missing on a prophecised quest. When they returned, Ashfur showed a surprising amount of relief for Squirrelpaw despite never being interested before the quest. While moving territories and Squirrelflight became a warrior, the two became close friends. Squirrelflight sought Ashfur's comfort after having a falling out with her crush, Brambleclaw. Ashfur assumed Squirrelflight's friendship were signs of love, being overprotective and possessive of the independent she-cat. When his desire to become mates with her was clear, Squirrelflight briefly considered it before asking to remain friends. Instead, she choose to rekindle her relationship with Brambleclaw, as she needed a mate to match her fiery personality, not contain it.
Although Squirrelflight turned down Ashfur's romatic pursuits as kindly as she could and politely explained her feelings, he refused to accept her answer, repeatedly stating he loved her. He even attempted to guilt-trip her by bringing up the fact that Brambleclaw was the son of Tigerstar, Brindleface's murderer. Squirrelflight, however, remained firm in her decision. Heartbroken and bitter, Ashfur ignored her completely, even with simple greetings. When Squirrelflight's medicine cat sister, Leafpool received a vision of Brambleclaw's future deputy position, Ashfur accused it of being fake. Soon, he began his life-long obsession with his former friend.
Ashfur's first major attempt at revenge was going after Squirrelflight's father, Firestar. He teamed up with Brambleclaw's RiverClan Half-brother, Hawkfrost to do so, who had a separate motive. Tricking his nephew and apprentice, Birchpaw into sending a false message to Firestar, Ashfur claimed ShadowClan's leader, Blackstar was trespassing by the Lake. During the investigation, Firestar was lured into a foxtrap, with Hawkfrost overseeing the crime scene. At the same time, Brambleclaw had been invited by Hawkfrost to the beach, unaware of Firestar's ongoing murder. While Hawkfrost tried to convince his brother to overthrow the ThunderClan leader, Ashfur backstabbed his crime partner. Asking for "help" from Squirrelflight and Leafpool, he exposed Brambleclaw and Hawkfrost standing over a dying Firestar. However, Brambleclaw rejected Hawkfrost's offer and was forced to kill his half-brother in defence of himself and Firestar. To Ashfur's disappointment, he'd accidentally made his rival a hero, enforcing Squirrelflight's love for him even more. While being medically treated, Firestar lost one of his nine lives as a Leader, having four left when he was revived. Luckily for Ashfur, his part in the crime remained unexposed.
In light of his failure, Ashfur went through a cool-down phase. Though he became visibly more bitter, he managed to hide the full extent of his emotions from his peers, remaining popular in ThunderClan. The relationship between him, Squirrelflight and Brambleclaw became restrained, but he pretended to tolerate them to avoid suspicion. However, this grew forever challenging when Squirrelflight had Brambleclaw's litter: Jaykit, Hollykit and Lionkit. Due to their parents, Ashfur naturally hated them. When their children became apprentices, Ashfur was assigned to be Lionpaw's mentor. To other ThunderClan members, Ashfur had the facade of a typical mentor. However, he was actually emotionally distant with Lionpaw, his praise often lacking enthusiasm. On at least two occasions, Ashfur allowed his hidden anger to publicly show, getting into violent fights with his apprentice during training sessions.
When Squirrelflight's three kits were given their warrior names, Ashfur was given another opportunity for revenge after so long. A thunderstorm caused a fire in ThunderClan camp, trapping the three siblings on a ledge. Wounded from a previous battle, Squirrelflight was unable to lower a branch to them. Discovering the scene with no one else around, Ashfur seized his chance. After lowing the branch at Squirrelflight's request, Ashfur suddenly blocked their only escape route, now in full control of who lived and died. Going into a long rant over his built-up feelings, accusing her of being faithless, Ashfur threatened to make Squirrelflight watch her three kits to burn alive. When Lionblaze prepared to leap at Ashfur, he ordered his former apprentice to stay put. When Hollyleaf almost fell, it eventually forced Squirrelflight to pretend she wouldn't be affected by their deaths, confessing they were adopted. Believing it would be more painful to be hated by her children rather than them simply dying, Ashfur allowed them to live. Though he vowed to expose Squirrelflight's secret to all four Clans at the next Gathering, in hopes of getting her exiled.
Over the next few days, the four family members begged Ashfur not to tell the secret in their own way. Yet Ashfur didn't care, despite being warned that ThunderClan's reputation could be ruined after a recent war and a whole family might be driven out. He even gave Jayfeather, a blind medicine cat, a second death threat for pestering him. With the Gathering just hours away, Hollyleaf saw no other choice but to kill Ashfur while he was out hunting alone. Even in death, however, the situation Ashfur started caused Hollyleaf to have a mental breakdown, committing her own crimes and subsequent self-exile. In a way, Ashfur was still able to succeed, as Squirrelflight was exposed at the Gathering by Hollyleaf. As a result, her mate and adopted children disowned her for years for lying to them. Meanwhile, her daughter, Hollyleaf went into self-imposed exile, allowing Squirrelflight to believe she was dead.
Unexpectedly, Ashfur ended up in StarClan, the holy afterlife of the Clans. When Jayfeather spotted him there through his powers, Ashfur angrily glared at his former victim before running away. When Jayfeather expressed confusion as to why Ashfur was in StarClan despite his crimes before his death, the spirit of Yellowfang claimed that Ashfur's only fault was "to love too much." Some time later, after Hollyleaf returned to ThunderClan, Jayfeather attempted to talk to Ashfur to learn the truth about his death, but was stopped by Bluestar, who insisted that he belonged in StarClan despite what he did for a reason.
When StarClan went to war with their evil counterparts, the Dark Forest cats, Ashfur apparently didn't get involved. Even when the Dark forest was leading a genocide against the Living Clans and Ashfur's sister, Ferncloud was killed, he didn't show up.
Over three years later, when Squirrelflight and her sister Leafpool were fatally injured in a rockslide and their spirits went to StarClan, Squirrelflght spotted Ashfur among her dead Clanmates. Ashfur didn't say a word to her, greeting her only with a dip of his head. Hollyleaf explained to a confused and unforgiving Squirrelflight that Ashfur had apologized for his actions, and that she and the other StarClan cats believed he had truly changed and didn't deserve to be in the Dark Forest. Ultimately however, Squirrelflight didn't join Ashfur in StarClan that day, as her physical body was able to wake up from its coma, reviving her.
|“||"I have no quarrel with Brambleclaw. I couldn't care less about Brambleclaw. It's not his fault he fell for a faithless she-cat. I know you think I've never forgiven Brambleclaw for stealing you from me, but you're wrong, and so is every cat that thinks so. My quarrel is with you, Squirrelflight. It always has been.[...] I can't believe you didn't know how much you hurt me. You are the blind one, not Jayfeather. Who do you think sent Firestar the message to go down to the lake, where the fox trap was? I wanted him to die, to take your father away so you'd know the real meaning of pain."||„|
|~ Ashfur threatening Squirrelflight at fire|
|“||"She could still see in her mind the blaze of rage in Ashfur's eyes, as if he'd forgotten he was fighting his own apprentice."||„|
|~ Ashfur attacking Lionpaw|
|“||“I don’t have to listen to any cat, let alone a scrawny excuse for a medicine cat. Besides, I already know what you’re going to say. You’re going to beg me not to say anything at the next Gathering. Well, you can save your breath. I’ll say what I want. That lying she-cat will be driven out of ThunderClan for good, and no other Clan will want her, either.”||„|
|~ Ashfur not caring about the effects of his crimes|
|“||"Birchpaw told me...Blackstar waiting on territory...Had to come alone..."||„|
|~ Ashfur attempting to frame Birchpaw and Blackstar|
|“||"Well, I can! Doesn’t any cat think it’s odd that Squirrelflight is Brambleclaw’s mate, and our medicine cat is Squirrelflight’s sister? It’s very convenient that she had a sign about Brambleclaw just now, isn’t it?"||„|
|~ Ashfur accusing Leafpool of lying|