First off. Mermaids exist. Kirishima is a Merman, an Alpha Merman. They are incredibly possessive and protective to their Omegas. Once a Alpha is seduced and wants to mate with an Omega, it will happen in a matter of days before the Alpha turns feral. Bakugou Katsuki is Half Mer-Half Human. His mother found love with a human years ago and the Mer race did not accept this, they banished her to the human world. The couple had two children, one boy and one girl. Bakugou fell in love with the sea at a young age and now works at a Mermaid research and housing facility a few miles off the coast of Japan. His sister is Yaoyorozu Momo. Their mother died after 13 years of being on the surface, their father died shortly after. Bakugou is 22 years old and he works in a huge (mostly submerged with a roof above water for helicopter landings and docking sites) research building. They take in injured Mermaids and nurse them back to health. A few of them choose to stay on for their lives.

Kirishima and Bakugou have been in a relationship for as long as anyone you ask could remember they were inseparable. They always knew what the other thought and what was going through the others mind. Kirishima is the alpha of the pair and Bakugou the omega. Kirishima got an offer to work abroad for 5 years. But that meant leaving Bakugou behind. He tried talking his boss into letting his boyfriend come along but to no avail and had to make a decision. He and Bakugou talked it over and over every night and they always came to the same conclusions. Kirishima should go. They finally made a decision and stuck to it, Kiri would go. They went on loads of date and made the other the centre of their life until Kiri had to go, but that time came to quickly and soon enough it was the night before Kiri had to leave. Kirishima wanted to make the night special so he made a romantic dinner and gave Bakugou the best sex he could before he had to leave. But they both forgot was that Bakugou's heat week had only just passed. -Art credit goes to popblam1 on Twitter-