If Ashfur hadn't been murdered, the series would have gotten interesting.
He walks along the river, while the thunderstorm rages on before the gathering. He wonders if he should tell the secret at the gathering. It would be delicious revenge on Squirrelflight for choosing Brambleclaw over him. But what would his punishment be for revealing such a secret? What If Brambleclaw attempts to kill him? What if…?
He sees a strange shadow just near him, and spins around. Seeing Hollyleaf leap towards him, claws outstretched, the look in her green eyes was hard, aggressive, icy, cold: he realizes she was willing to kill him. He dodges to the side, and used his front legs to knock Hollyleaf's legs out from under her. He scrambles to his feet and races away, and climbs up the Sky Oak.
Hollyleaf runs past, not realizing he had climbed the tree. Unable to smell him out in the thunder storm, she leaves and heads back to camp.
Ashfur cautiously makes his way back to camp, just in time to catch up to Firestar's Gathering patrol.
On the way to the gathering, he was willing to tell Squirrelflights secret to the four clans. But he had a better idea, on what could hurt her more: Finding out who the kits parents really were, and dragging them through hell too.
So he keeps quiet, glancing at Lionblaze, Hollyleaf and Squirrelflight throughout the gathering, smirking at the panic in their eyes, the worry of when he'll open his mouth. It made him feel powerful: And he loved it.
When the gathering ended, Ashfur walked home, trying to remember the details of the kits birth. Squirrelflight had walked back to the Clan, with the kits… With Leafpool! He glanced towards the tabby she-cat as they walked back, taking note on how weary she looked. "Surely she must know who the parents are." He mused to himself.
Once back at camp, he starts to get to work on finding the truth, not knowing the three were doing the same. He starts to suck up to Leafpool, helping her with tasks when Jayfeather isn't around, eating fresh-kill with her and chatting to her all the time. Unaware that Squirrelflight had told Leafpool about what he had threatened. So Leafpool plays along, if only to keep Ashfur from finding out the truth.
Eventually the next gathering starts to draw near, and Ashfur becomes frustrated with the lack of progress he's made. After Honeyferns death he notices an angry Hollyleaf storm into the Medicine cat den, his curiosity peaked, he sneaks near the entrance and overhears what he wanted to hear. That Leafpool is the threes mother. Satisfied he leaves before anyone notices him, and it doesn't take him long to put two-and-two together to figure out Crowfeather is the father. Excited, he requests to go to the Gathering again. However Firestar refuses, not seeing why a fully grown Warrior keeps wanting to go to the gatherings like an eager apprentice. He chooses his patrol: Brambleclaw, Sandstorm, Leafpool, Jayfeather, Lionblaze, Hollyleaf, Sorreltail, Squirrelflight, Ferncloud and Cinderheart.
Angry, he waits until the warriors leave for the Gathering, and follows the group closely, avoiding detection by staying 10 foxlengths away from the group, and taking cover in Windclans gorse bushes and dips in the hills.
He gets there, just in time to see Hollyleaf reveal her true parentage to the entire Clans, and watches the havoc break out. He expected to feel glee seeing Squirrelflights life break down in front of her. But the feeling doesn't come. He just feels empty as he watches her life fall apart.
Confused and dismayed , he makes his way back to camp in a hurry, catching a rabbit on the way back so cats think he was out hunting. He goes to his nest and goes to sleep. Only to wake up to a meeting: Leafpools Medicine cat duties being taken away from her, and the news Hollyleaf had died hunting in the tunnels.
He notices Whitewing watching him nervously, and after the meeting asks to speak with him in private. They do so, and Ashfur learns he might be the father to Dovekit and Ivykit. But Whitewings tells him no matter what, the kits will be raised to think Birchfall is the father.
Over the fourth series, Ashfur starts to become more and more detached from reality. Unable to go near his possible kits in case the Clan starts talking. Having to watch his back constantly, believing Squirrelflight or Lionblaze might attempt an attack on his life. He eventually stops grooming himself, and moves into the abandoned Twoleg Place, hiding away from his clan. Despite numerous Warriors attempts to try and get him to come back, he refuses or ignores them, unable to deal with the pressures of being a Warrior, in an environment which he is practically responsible for messing up.
He continues to stay away from the Clan, especially after Hollyleaf goes back to the clan.
Eventually the fight against the Dark Forest happens, and Ashfur is encountered by his mother, Brindleface while in the forest. She tells him that family is the most important thing in the Clan, and right now his family needs him. Seemingly awoken from his daze he races back to camp, thinking his possible kits are in danger. When he gets there, he hears a scream from a familiar voice - Ferncloud! He races into the Nursery and barrels into Brokenstar hurling him away from his sister. Enraged, Brokenstar leaps forward and rips Ashfurs throat out, and life slowly leaves his body after Yellowfang kills her son a second time. He closes his eyes to his sisters cry of grief, begging him to get up, and she always loved her brother.
His spirit leaves his body, and heads for Starclan. He is let in only because he saved his sisters life, considering it a noble death even if other cats believe Ashfur never changed. He ends up avoiding Hollyleaf in Starclan, knowing it wouldn't end well for either of them. He spends the rest of his days watching over Dovewing and Ivypool, knowing that while he is only the father to one of them, he was proud of "his" kits.
The only cats who acknowledge him properly in Starclan are Birindleface, Fernclouds kits (Shrewpaw, Foxleap, Larchkit, Hollykit and Icecloud) and older warriors who do not know about Ashfur or his dark deeds.