Nereid

Origin
Claudia Landry was in love with a Merman named Jeran, who was a prince among his people. He gave her a magic necklace that allowed her to live with him beneath the seas. It was not all happiness though: clan wars, human (and superhuman) encroachment, ancient magical creatures and even the gods themselves threatened their way of life. Claudia became a skilled warrior in her own right, and the pair of them fought together against all comers. Their exploits even came to the attention of the surface world, including some super hero teams that have tried to recruit them.