Lorelai is a shape-shifting mermaid and Princess of Terrapisciss. She is also one of Ben Tennyson’s love interests in the comic version (Ben 10 Comic (IDW)).
Lorelai is descendant of explorers from Pisciss. She lives in a moving city, Terrapisciss, with her mother Queen Beatrice La'mer.
- Lorelai page on Ben 10 wikia.