Shoto Todoroki and Katsuki Bakugo are Childhood Bestfriends since 4 years old from the Kindergarten in the past.

Though at the Journey in U.A they had some rivalries with each other, that doesn't mean they weren't friends, They still are now

Katsuki knows Shoto has Trauma, Hell the guy seems to like his OWN house than Todoroki Household, The Bond They have is inseparable and It's not like Katsuki is going to leave at all anyways...

"Birds of a feather"

-My Hero Academia-