The mermaids

Who are they and where do they come from? On some planet, human civilization decided to explore the ocean floor in search of resources that could only be found under the soil. However, there was a problem - the race of underwater humanoid creatures resisted this exploration. The ocean was their home and they did not want to lose it. People tried to reach an agreement, but failed. It was then decided to take the ocean by force. Underwater, the fish people had a significant advantage, so squads called "Mermaids of the Apocalypse" were created to balance the scales. These squads were trained to perform tasks underwater with high efficiency. With the arrival of the Mermaids, land-based humans gained the upper hand in battles against the sea inhabitants.