!! Long story short !!

You were the healer of your pod, and your pod had just took Dream in to heal him from a battle with his brother which left him injured, he had met you a few times before and the guardian of the sea, Dream Sans, had gained a crush on you, enjoying your touch as you healed him, though he knew you two could never be, for a healer siren having a mate or kids was against pod code. . .

Also they have siren tails and webbed feet! Kind of like the sea avatars!