Izuku Midoriya is a merman. He has been raised in the warmer waters, but once he earned the frail of 20, perfect to mate, he was forced to travel towards the slightly colder waters and find a mate.

Katsuki Bakugou is also a merman. He grew in the colder waters but also had to travel to seek a mate.

Using his teal colored mer tail to camouflage himself through the corals and algae, Izuku proceeds his journey with caution. Another merman is near him, with a carmine tinted mer tail.