A black metal song in episode 41 of My Hero Academia
From what I can gather, the only artist mentioned in the end credits is Miwa. After hours of searching all I could come up with was this video of her doing a metal cover. https://www.youtube.com/watch?v=8eVHPqmgvrE It sounds close, but Im not 100% sold on it. But it does prove she can sing that style so perhaps its a new song by her. If that is the case we will have to wait for the OST.