Kindergarten (1/2)

In a world where everyone develops a quirk and two marks at the age of four, one representing them, and one representing their soulmate

How come Kirishima, Bakugou and Todoroki all share the same one? Who was their mate? Surely they already know, so why haven't they appeared yet?

( Non-canon compliant on most of the part )

( May not have a happy ending )