In this alternate universe, Deku develops a quirk, but it's to powerful for his own good. He ends up killing his parents and running away until he passes out in the ocean. There he meets the person who made a difference in his life: Pototat! JK. Oyogu.
Just after Minato's death, Kakashi's heart is broken. To get his mind off, well, everything, Sarutobi sends him on a long term mission to protect Harry Potter. Easy right? Simple in and out. As if. (Set in the prisoner of Azkaban. Harry is thirteen, Kakashi is fourteen.)