Some Things Stay the Same

BKDK (with their prototypes only in the first few chapters)

Even after all of the years they've been apart, Katsuki still thinks about that boy he befriended in highschool from time to time. How down to earth he was while managing to snap and throw back insults at every poke and prod Katsuki put him through. The intensity their debacles can be in class and out that showed a side of passion Katsuki wished to see on the boy more often. The way dark hair, tangled and fuzzy from the lack of taking good care of them would sway and jump, always covering at least one eye as they observed and analyzed everything and anything around him in quiet observation.

But now, thoughts of him come unbidden after meeting a boy, introduced by the name of Izuku, with a blinding smile and a personality able to sway anyone in comfort and safety.

They couldn't be the more opposite, but Akatani Mikumo is a constant image in Katsukis mind.

Or

Akatani Mikumo is given the opportunity of a new life and does his best to forget everything that had to do with his younger years, including leaving behind the name he was once known by. The variable known as Katsuki throws him a little off balance.

(The summary is a work in progress)