Tanjiro was something forbidden. Something that should not have existed. Something that was the key to defeating Muzan. Son of the demon king, Muzan Kibutsuji. And son of the most powerful demon slayer in history and the first user of the breath of the Sun, Yoriichi Tsugikuni. Son of Good and evil. Son of Yin and Yang.

Amidst a violent snow storm up in the mountains, two demons were sent out to extinguish the last living relations to the sun breathers. The Kamados. "Oi stop messing around you woman obsessed freak!" "Come on don't be so up tight!" "Huh... what's this?" A small child appeared from behind a snow covered bush, a small note tied to his neck as his bright red eyes stared at them inquisitively. "Tanjiro Kamado... you don't say" **** "You are to infiltrate the demon slayer corps and gain their trust Tanjiro. I'll always be with you, don't forget that" the demon king stated, his tone surprisingly soft. "Yes father"

The stories of the Tsugikuni Twins were passed down onto generations of the Demon Slayer Corp. The twins have died long ago but what they didn't expect was for the sword belonging to Tsugikuni Yoriichi to turn red once again. #1st in Yoriichi on 6th of May 2021 #1st in Michikatsu on 1st of Oct