(WARNING: BAD ENDING/DEATH)

Not very detailed but one of my fav Gofushi headcanons is Megumi summoning Mahoraga for someone else, but Maho targets Gojo instead. At some point, Gojo uses Hollow Purple and instead of HP hitting Mahoraga ........ it hits Megumi instead (who stood behind Maho or something like that)

Gojo never stops blaming himself for Megumi's death