Slayers and Heroes (BNHA x Demon Slayer Crossover)

WARNING: contains spoilers for those who don't read the Demon Slayer Manga Right after the battle of Upper Moon 1, and right in the middle of a battle with Kibutsuji Muzan, a bright light comes out of nowhere and they all black out. Right after the villains attack at the USJ, these strange people come out of nowhere ...