Got inspired after watching the movie Venon.
So once again there isn't much i can add when it comes to MHA fsnfics since the anime isn't finished (Haven't read the manga so idk if its complete)
The MC dies and ends up in the void where he meets god. Due to low karma points the MCs fate will be decided by a spinning wheel, it will pick the world and a power/ability/weapon.
The MC ends up getting the world of My Hero Academia and the Venom Symbiote as his/her quirk.
You can make the MC become an anti-hero, villian or a hero but since Venom has a consciousness of its own you would probably become an anti-hero... Villains are ass plus All For One would just steal yo shit.
You could also make it that Venom doesn't feel hunger like in the movie so he wouldn't have to kill poeple (Unless you make the MC a villain)