Vessel (слэш)

Bakugo Katsuki had been his first and best friend. They’d both dreamed of piloting mechas that could defy gravity and skim the waves of storm clouds. They had argued about who would become the best pilot, the kingdom’s champion, second only to the vessel.
Then Katsuki’s parents had died, and his godmother, Queen Rei had taken him into her household. Almost overnight, Katsuki became a prince, far too above Izuku’s station to remain friends with him. Severe looking attendants had spirited Katsuki away to royalty approved tutors and whatever else princes were supposed to do, and Izuku had never seen him again. At least not in person. Every time Izuku had caught a glimpse of his friend at some broadcasted public event, he'd catalogue all the ways he'd changed. How tall he'd grown, how broad his shoulders had become, the lean lines of his jaw, and the angle of his cheekbones.
That boy was now as much out of reach as his dreams of becoming a mecha pilot.
--Or--
Izuku is a mecha pilot in training who inadvertently becomes the vessel to One For All, the kingdom's most powerful weapon. Then he gets kidnapped by Katsuki. Lots of angst, bickering, and horny happenings ensue.