It sounds to me like Debi and Oceanid would get along swimmingly. ^^ They both live near water, both are teens, both are demons, and both like mischief.
Would you like to RP them together? I'm not sure what they could do... it's been a while since I RP'd either of my Pae, I'm not sure what's been happening on the island. The last time I RPd, there was a confusing meta plot going on. ^^;