Tanjiro: Fire Hashira, 19

Zenitsu: Rumble Hashira, 20

Kaigaku: Rumble Hashira, 20

Kanao: Flower Hashira, 20

Aoi: Water Hashira, 20

Nezuko: Blood Hashira, 18

Genya: Demon Hashira, 20

Inosuke: Beast Hashira, 19

Senjuro: Flame Hashira, 18

((in this au muzan would be master, kagaya is muzan, Hashira are uppermoons))