Thetis

Thetis is a female youma under the direct control of Queen Beryl in episode 012. Her mission is to help Jadeite gather energy from human beings in order to revive Queen Metallia. She is a very powerful youma who can control seawater. She seemed to have romantic feelings towards Jadeite, and appeared before him at the beginning of the episode with an idea to help him steal energy. In her human form, Thetis has light skin, blue hair, and dark green eyes. She wears a short blue dress with light blue gloves and white shoes. In her youma form, she has chalk white skin, dark blue (almost black) hair, and glowing red eyes. She does not appear to have a mouth, but her jaw moves when she speaks.

She wears a blue, sleeveless, skin-tight suit with lavendar gloves that reach past her elbows. She also has an elaborate gold headdress. Thetis's name is derived from the name of the Greek goddess Thetis who was one of the most well-known Nereids. The Nereids were sea nymphs who were helpful towards sailors.

(Source: The Oracle :: BSSM Encyclopaedia)