Seraphina, as she is a mermaid, has the upper body of a woman and the lower body of a fish. Her fish scales are dark green in color and she wears a purple top. Her hair is black and goes past her shoulders. She ornaments in her hair with a shell nearing the right side of where her hair parts on her head. Another distinguishing feature, other than her obvious fish tale, is a mole near the bottom left of her mouth and chin. Seraphina also sports some sort of tattoo on her right forearm. Seraphina is unique in her build; she is stockier than most other females on the show.
In There's Something About Hook Foot, Seraphina meets Hook Foot while he is collecting firewood. As is revealed later, she is merely trying to use him to hide the stolen mariner's pearl from those seeking it. She slowly falls for Hook Foot and by the episode's end she gives herself up so the Vodniks let Hook Foot and the gang go in peace. Later at the beach, we see Hook Foot getting over the loss of Seraphina when suddenly a mermaid's tear appears, followed by hundreds more, implying Seraphina, too, was in agony for having to leave Hook Foot.