Izuku was ten years old when he met Katsuki aka a merman that the Toshinori Aquarium Palace called Dynamight. As Izuku aged the merman never left the back of his mind it was one of the reason why he decided to become a marine biologist. He not only wanted to because of his love for salt and fresh water creatures, but to study Katsuki's species. Merfolk were rare and well the more they talked the more Izuku fell in love with the merman. Maybe he had always loved him. CW: Fluff/Small age gap/Light angst/Teratophilia/Smut. Also I don't own any of the characters credit to Horikoshi Sensei. Started: May 17, 2022. Finished: Nov 14, 2022.