Learn to Smile (Experimented AU BakuKiriKami)

Kaminari was kidnapped at the age of 5 by an highly wanted assassin named Silver Jones. He was taken to the boss who hired Silver and put into a 'hospital', where they experimented on kids with quirk based things. (The place where Eri would come from, run by Overhaul but before that owned by Overhaul's older brother).
Ten years later, UA and the pro-heroes hear news of the place where Eri originally came from before living with Overhaul. They send Class 1-A as well as several pro-heroes to save the young children, however, one of them is way older than they expected.
Two blondes soon become friends, and maybe even more?

TRIGGER WARNINGS
Violence
Trauma
Mentions of R@pe but no detailed scenes only mentions during PTSD moments.
Omega in a human world.
Cursing (It's the Bakusquad y'all ;-;)