This Bitch gives their stories Daddy Issues

Solar Phoenix

There is a demon that lives on that mountain.
It scares off anyone sho comes near with terrible snarls and bared claws.
They say it's eyes have been turned red by bloodlust. That blood has stained it's hair the same.
They call it the Blood-Eyed Demon. They say it's eyes are the most terrifyingly beautiful things you'll ever see.
If anyone in town dissapears it must have been because of the Blood Eyed Demon. It must have eaten them up like noontime snacks, washing it's hair in the blood.

So of course a Hashira was sent to check on the situation.

Tomioka wasn't expecting much. Though there were several conflicting stories on the demon. Some said it came out in the day which was ubsurd. Other's claimed it's hair was not red but black. Some said it's eyes were actually just rubies inkaid in it's skull. Some described it as female, other seemed certain it was male. All in all he didn't have much concrete description.
Though he didn't end up needing one.
It lunged at him, glistening fangs bared, claws curved and tipped with crimson, stained with blood no doubt. It's hair was indeed red and it's eyes were not rubies though they were certainly intriguing. But Tomioka only had a moment to admire the creature before the reality of the situation came crashing in.
It was still light out.
The sun still high in the sky.
This demon was walking in the sun as if it were no great feat.

Blah blah blah

Tomioka takes him back to HQ with his sister Nezuko who he's been protecting this whole time, she's human, has a damaged right leg and brain damage causing narcolepsy.

Everything is tense but going okay is until Sanemi shows up, he doesn't give a single person a second to talk and just starts swinging his sword.

Tanjiro barely block the blow and looses both hands and takes a deep cut to his chest as a result.
Nezuko is horrified.
The Pillars wait for the blood to slow as they try to assure the frantic girl her brother will be fine.
He does not stop bleeding.
His hands do not regrow.
His cut does not heal.
And his heaving chest stills, eyes going blank.
Tanjiro died. In the gravel of the garden. Before the Hashira. At Sanemi's hands, and his head slumped into his sister's lap as time stopped.
Nezuko's wails shook headquarters. The Hashira were speechless, a huge advancement a demon that walks in the sun and protects a human. It couldn't heal, and it had just been killed infront of them.
And worst of all, in front of it's still living still human sister, who rocks back and forth cradling her brothers head, begging him to wake up. Sobbing and screaming. Absolutely destroyed.

And then he starts disintegrating. The Hashira wince as the girl gasps and clutches at his wounds as the flesh around them falls away. Sparks and flakes carried off by the wind as she begs and sobs. Don't take him away. Please no. At least let her bury him. If there is any loving God out there at .east let her bury him.

And then he bursts into flames.
Nezuko screams and whips back her hands as they are burnt by white hot flames, the demons eyes glow as bright as the sun in his sockets and he sucks in a breath, glowing life full of sparks and dancing flames fills his mouth and floods his lungs, he coughs out a few sparks and a lot of smoke, his hands were rebirthed from the flames, his kimono is singed but the wound is healed. Nezuko collapses.

The demon takes a moment, clutching at his once still but now beating heart, eyes dazed and unfocused as he pants and heaves, embers and heavy smog falling past his lips.
Then he sees Nezuko. And the pure humanity that fills his eyes make everyone present gasp.
He scoops her into his steaming arms and feels over her teary puffy face, red from crying.
He mutters something too jumbled and hoarse to make out. Hardly even Japanese.
Then he catches sight of Sanemi's blade.
He looks panicked. Scared. Exhausted.
The slightest movement leaves him panting with exhaustion and from the way he's staring at Sanemi hunger and fear are fighting a fierce war in his head.

He runs.

Nearly a year later they track him down again.
Run him out of the woods only to corner him, he barely escapes, loosing a leg to Gyomei's flail. The blood loss from this and all the stress causes an extremely high fever.
After days of running and hiding in their own woods like terrified prey it finally gets the best of him. He dies when Nezuko is out washing his bandages. She comes back to find him panting, leg returned, smoke falling past his lips again. And she grieves.

Obanai finds them in the midst of her grief and they are forced to run again.

When they finally corner the siblings Nezuko has thrown herself over her brother to protect him from their blades, he is weak. Curled up in a ball, panting and wheezing. Coughing and shaking, eyes far in the distance.

They take the sibling back to headquarters by force.

After that it a slow process of them learning to trust Demon Slayers again.

Idk. could be cool.