Just_Yang
What if Tanjiro couldn't be saved? What if demon slayer is my hero academia's past? Combine those two questions and you get the trio: Girou, Shoune, and Yuuna. Three slayers equipped with superpowers called quirks are on their way to end the demons, once and for all, finishing what their ancestors' started.
(Cover is work in progress, so for now it's a temporary one)