Transmigrating to the Interstellar Age: The Admiral Has a Little Merfolk

Quick Transmigration Story with a Powerful Male Lead from the Interstellar Era Who Belongs to the Merfolk

All I remember is that in one story, the female lead transmigrates into a world where she's one of only three humans in the interstellar era. She's assigned to live with the merfolk. The other two are a man and a woman. I think the man ends up with the beastfolk, and he's really scared because he thinks they all look terrifying.