Half-Demon! Tanjiro AU

Chapter One: The End is Only The Beginning

Warnings: A LOT of angst and a bit of violence.

Word Count: 3010

The sun had finally risen over the horizon and it seems that the battle had finally come to an end. The giant infant-like form of Muzan had finally disappeared, leaving the surrounding slayers devastated and wounded. "Lord Kamado! Lord Kamado!" One of the Kakushis yelled as they knelt down beside the form that was Tanjiro Kamado.
The young boy looked like he was on an unconscious state. His head was facing the ground as he sat on his knees. Tanjiro's remaining arm was limp as he sat there, back facing the sun. Giyuu Tomioka, who had also been severely injured along with many other slayers, took his place in front of the young boy.
"He's not breathing and he has no pulse!" The Kakushi yelled out in pain. Giyuu's eyes widened in horror when the news rang in his ears. The others around them weakly looked up at them with the same look of horror. Giyuu fell to his knees and took the remaining hand of the boy. "I've failed to protect you again...Forgive me." He lowered his head in shame. "I always receive protection from others.."
The dam had finally broke as everyone started to mourn Tanjiro's death. So many lives were lost during the final battle..so many..and his death was the straw that broke the camel's back. Inosuke and Zenitsu trudge their way towards the young slayer, tears filling their eyes.
Something rumbled within Tanjiro's body. He slowly started to lift his head up, but nobody noticed due to their grief. "In my place..you must destroy..the demon slayers!" Muzan's voice rang in Tanjiro's head as his wound healed and he opened his eyes. They were scarlet..just like Muzan's.
The young boy immediately swiped Giyuu away from him. The Water Hashira fell back, perplexed as to what was happening. Tanjiro jumped away from the group and roared ferociously. His arm had completely regenerated and he was snarling at them like a hungry beast.
"T..Tanjiro?" Giyuu spoke weakly as he looked upon the boy in absolute terror. Tanjiro raised his regenerated arm to his mouth, wiping off his saliva. "No way..Tanjiro?" Zenitsu winced as he was held up by a Kakushi. Inosuke stared at the boy in disbelief. Tanjiro looked straight at Zenitsu, eyes shining with hunger.
Off in the distance, Nezuko Kamado came running closer and closer to them. Her humanity was flickering within her. Due to Tamayo's medicine, her body was having a hard time deciding whether or not she was a demon or a human. Nonetheless, she was going to do what she had been doing for the past few years..Defend her brother.
"Oni-chan!" Nezuko called out to her brother as she steadily approached the scene. Tanjiro looked at her and snarled, causing the girl to yelp. "Get back!" Giyuu yelled as he picked up his sword, grunting as pain surged through his body.
Strangely, Tanjiro only stared at the young girl. He looked like he was dazed, like he had no thoughts behind his eyes. Then, the young boy cried out. His roar cut through the skies like a knife through butter. Tears flowed down his face as he struggled to speak. "Grr.ge..get..GET AWAY FROM ME!"
Everyone stopped and stared at him in disbelief. What was going on? Was he fighting back against Muzan's control? Tanjiro snarled as he looked for a way out. The young boy bolted directly for Nezuko. "No!" Inosuke yelled as he rushed to protect her. Nezuko covered herself with her arms, preparing for the attack.
But the demon did a strange thing. He jumped over both of them, using them as stepping stones, and ran off into the forest. Zenitsu struggled out of the Kakushi's grasp and landed on his knees. With tears filling his eyes, the blonde watched helplessly as Tanjiro ran. "TANJIRO!!" Zenitsu screamed in agony as the last glimpse of the young slayer disappeared.

The mess that the battle had left was extremely scarring. Many had died and needed to be buried. Kiriya and his sister, Kanata, came to assess the damage. "Where's young Kamado?" Kiriya asked tiredly as he walked over to where Muzan had been killed.
"He's gone.." Giyuu had fallen back on his knees, wiping tears from his eyes. "Gone? Do you mean..he's dead?" Kanata put her hand over her mouth, sickened. "No..He ran..He's.." Giyuu tried to mutter the awful terrible words. "He's a demon.."
Kiriya's eyes darkened as he felt shame overcome him, like a weight inside of his stomach. He shook his head to shake off any haunting thoughts, but it was to no avail. "Forgive me, Tomioka. The losses that have taken place in this battlefield..have destroyed us all.."
"We can't just sit here and wait for him to come back!" Zenitsu gritted his teeth, turning to face their leader. "We have to go search for him!" Everyone looked at him in awe. Even after all that fighting, he was still willing to get back up. "But we can't find him like this!" Nezuko cried out, knowing that they would all get killed.
"Miss Kamado is right." Kiriya inhaled, relief resting in his heart. "We will take you to the Butterfly Estate to heal and recover. In the time being, I will send out tracking teams to search for your friend." The young leader nodded to the crowd that had perched above them. They cawed before taking off to the woods where Tanjiro was last seen.