I'm making a story. I have a female superhero character.
She live in normal Earth, without any combination of legends. She was a normal human in the past, but an experiment caused her to have superpowers. She can live both in water and land. But, her superpowers are optimal when used in water. Her superpowers are almost same like Aquaman's.
I need ideas for a villain for her to fight. I think, it's best if you come up with underwater villain ideas. I have searched for Aquaman as my reference. But, Aquaman is different with my superhero character, he is a human-Atlantean Hybrid, while mine is pure human. You can use another reference for your ideas, rather than Aquaman.
Please give detail villain ideas, including his/her origin, name, appearance, powers, and motives. Thanks