Chapter Text
Giyuu can’t believe it.
After so many years of trying to rid Muzan and demons from the world, they’ve finally done it. This should be cause for celebration.
Instead, all he feels is despair.
Fighting Muzan cost him his precious omega. The only person he’d given his heart to. The largest loss since Sabito. Losing Sabito was scarring, life-altering, but a reason to continue the fight. Losing Tanjiro made it all seem pointless.
He hadn’t grown at all since losing Sabito. He was still that weak child, unable to protect the people worth more than the world to him.
Giyuu kneels in front of Tanjiro’s motionless body and grasps his hand tightly within his own, “I’m so sorry Tanjiro. I’ve failed to protect you. I’m so sorry,” he sobs, “I’m sorry Nezuko. I wasn’t strong enough to protect him.”
Tanjiro’s soft amber scent suddenly changes, and Giyuu’s head snaps up in response. What is this putrid smell? It smells like a burning building, blood, and gore.
He watches in shock as Tanjiro lifts his head to the sky. “Tanjiro?” he softly calls. The air around them turns even more acrid, strong with a sudden violent curl. Giyuu lunges at the closest Kakushi, screaming, “Watch out! Get away from Tanjiro!” seconds before his omega reaches out with sharpened nails, intending to maim flesh.
The Kakushi grunts with Giyuu’s full weight colliding into him, pushing him into the ground.
The other Kakushi surrounding Tanjiro look at Giyuu in confusion before turning their eyes onto Tanjiro. They watch as he quickly lunges towards another Kakushi, before lurching back, screaming in pain.
“Tanjiro!” they shout, frantic, moving to help him.
“Get back! Get away from him!” Giyuu grunts, scrambling upright.
“But he’s hurt!” One shouts, before watching in horror as Tanjiro’s face begins to burn, steam rolling off the boy in waves.
Tanjiro screams and wails in pain, clutching his burning face. His eyes dart around, before settling on the shade of a nearby building. He rises to his feet before making a quick dash towards the sanctuary.
“Get back! He’s become a demon!” Giyuu yells before launching himself at his omega, “Anyone capable of holding a sword, get over here quick! Tanjiro’s become a demon! Keep him out of the shade, burn him while he’s still weak!”
Giyuu holds back a sob as his body collides with Tanjiro’s, pushing him into the ground. His alpha screams at him to fix their omega’s pain, to bring him relief. He struggles with Tanjiro for a moment, before, to his horror, his face stops burning and begins to heal. Shit, he’s already resistant to the sun? It’s not all that surprising, considering Tanjiro’s strong will, and his genetic connection to the sole other demon in history that resisted the sun.
Momentarily lost in thought, Giyuu feels Tanjiro’s body seize before he throws Giyuu’s body off his own. The omega quickly stands upright, growling at the alpha in front of him.
Giyuu’s heart clenches as he meets his omega’s eyes, no sign of recognition within those now pink irises.
First his omega seemingly dies, then he’s reborn as a demon. Now, he has to fight his darling, with no idea how to end his life. Giyuu frantically recalls information about Muzan, any hint of a weakness he can exploit. Muzan couldn’t be killed by decapitation, only exposure to sunlight. With Tanjiro immune to the sun, is there even a way to kill him? His heart aches at the thought of hurting his omega, but is this even his omega anymore? He smells almost entirely different, doesn't seem to recognize him, and tried to kill their comrades. Tanjiro deeply values the corps members, there's no way his omega would be able to cause significant harm to one of them not threatening his loved ones.
Giyuu barely has a moment to despair before Tanjiro’s growl crescendos and he launches his body at Giyuu, nails aimed at his throat. Giyuu clenches his sword tighter, body aching with his numerous injuries, and hesitates to swing his sword. His beloved omega, his darling Tanjiro. He can’t do it, he can’t swing his sword. Giyuu whispers, “I’m sorry, Tanjiro,” before closing his eyes and allowing his arms to fall.
Giyuu opens his eyes when he hears a thud and yelling. During his surrender, Inosuke has gotten between them, and is yelling at his omega. His alpha immediately bristles, how dare he raise his voice and sword to his omega? He attempts to squash the rage flooding his blood. He takes a second to recompose himself, arguing with his alpha. They need to put Tanjiro down before he’s completely gone, end his misery before it truly begins.
The smell of blood hits his nose, his head snapping up at the scent. He’s shocked to see Nezuko has appeared in the confrontation during his moment of distraction, attempting to console Tanjiro. He barely has time to scream at them to fall back, before Tanjiro sinks his teeth into his sister’s shoulder.
There it goes, Giyuu’s last hope at saving his precious Tanjiro. He’s tasted blood, he’ll go into a frenzy and slaughter everyone around him. His heart and alpha cry in despair and grief. How much more is he expected to take? He’s lost countless friends and comrades in the fight against Muzan. Now, he’s lost his other half.
His other half will be the one to take the rest of his comrades, including his sister-in-law.