Basically Bakugou finds Izuku as an elf that can change sizes and has to protect him. Bakugou finds out that Izuku has healing magic. (Because it's fantasy and not modern. So there's no quirks. It's considered as magic, or transformations.) Early when Bakugou had just met Izuku and tells him what he is. An Ultima. (You Aphmau fans all know what this is. 😂 for those of you who hasn't watched Aphmau...GO. AND. DO. IT. SHE. AMAZING. Oh yeah. She does Mc Rp on YouTube.) Bakugou and Izuku help each other out. They are both the last of their kind and were considered myths and only legends.