Age: 15

Gender: Female

Birthday: November 21

Nationality: Denmark

Height: 165cm

Weight: 52 kg

Blood type: O

A loyal servant of Poseidon, bound to him by a debt of life. Thetis was saved by Julian Solo when he was a little boy, she was then a beautiful fish, stranded on a beach, but Julian tossed her back into the sea.

During Poseidon's kidnapping of Athena she served as mediator between Poseidon and Athena's factions. She was unable to assist her fellow Mariners due to her defeat by Ophiuchus Shaina. She was spared by the Saint, and rescued Julian Solo from the Underwater Sanctuary collapse after Athena removed Poseidon's soul from him. Thetis turned back into a fish as she died, and Julian, upon finding the fish, let her back into the ocean, finally laying her to rest.