3(BNHA)

An Au where everyone is born with a soulmate(it can be platonic or romantic).

Since they were babies, Bakugou and Deku knew they were soulmates as their soulmarks(what it is, is up to the writer) are the same but with Bakugou's being as green as Deku's eyes and Deku's being as red as Bakugou's eyes.

They were always glued to each other to the point people weren't even sure if they would be platonic or romantic soulmates.

But when they were around 10, something happened that make Bakugou start pushing Deku away and hate him which confused and worried everyone who tried everything to make them make up but nothing worked.

The truth was that a day when both were playing in a park a villain attacked which ended with Bakugou watching Deku die and feel the pain of losing his soulmate while his soulmark disappeared leaving behind a burn mark.

But before the authorities could declare Deku dead and inform his family, Deku suddenly opened his eyes which ended with everyone saying a miracle happened but Bakugou knew that whatever opened his eyes couldn't be Deku or Deku's quirk being that he is immortal as if that was true then his soulmark would still be there but when Bakugou tried to inform the heroes and authorities present about it they ignored him.

Whatever was in Deku's body continued acting like Deku but with what was Deku's love for his soulmate becoming an obsession that after they became teens started to scare Bakugou as no matter where he went, 'Deku' was there.

Things continued like this until they entered U.A where things started to change(what is up to the writer).

What took over Deku's body could be a evil spirit, an alien, basically anything but Deku so the writer can decide that as well as how this will affect the plot, if there will be a ship, if Bakugou will have to suffer forever with 'Deku' in his life, etc.