You get called Akru by Muzan and He gets called Akaza by Muzan, You and Akaza are siblings, Akaza is the original upper three and your also upper three since your his little sister, tanjiro had cut off both of your heads and is staring with his sister nezuko and the flame hashira Rengoku as you and Akaza both argue as y’all crumble away but your crumbling away faster then Akaza.

“I was busy fighting the Flame hashira!” Akaza yells at you