When the Lights Fades

Countains manga spoilers.

After beating Muzan, everyone was... Delighted. "Wait! Tanjiro!? Is he fine?!" Cried Giyuu, Water Hashira. Although some Kakushis tried in vain to calming him down and avoid moving, but he did not listen and rushed to a young man on the ground with one arm less, Tanjiro. Giyuu lowered himself to his level trying to see if he was awake but no signs. The Water Hashira began to panic but a few seconds later, the boy who was unconscious raised his head and opened his eyes slowly. But... instead of his usual dark red eyes, they were crimson eyes with pupils like those of a feline, or... pupils like Muzan, the now dead Demon King. "Tanji...-" Giyuu did not have time to express his shock when the boy he had previously saved, made him lose consciousness. The new Demon then took the opportunity to jump to the highest point of the building and became acquainted with the place. After a few moments, he whispered "Blood Demon Art: First Form, Fukkatsu*". A blinding light followed can after the end of the incantation.

Fukkatsu*= Resurrection

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This is an AkaTan AU, so if you don't like the ship, please don't read