|Lives:||D Point, near the North Pole|
|Occupation:||Youma under the command of Queen Beryl|
|Associates:||Queen Beryl, Jadeite|
|Aliases:||Posing as a crew member during Operation Romantic Cruise|
|First Anime Appearance:||I Want a Boyfriend Too! A Trap on a Luxury Cruise Ship|
|First Manga Appearance:||N/A|
|First PGSM Appearance:||N/A|
|English Name:||Titus (DiC dub), Thetis (Viz dub)|
|Actors:||Miki Itou (anime), Maria Vacratsis (dub)|
Thetis was one of Beryl's most powerful Youma, which led Beryl to be angry with Jadeite when Thetis was killed. She was also one of the few Youma to be shown with any real personality and depth, with her love for Jadeite and determination to prove herself to him, even though she had to disobey Beryl's wishes to do so. After she was distracted and confused by attacks from Sailor Mercury and Sailor Mars, she was destroyed by Sailor Moon's Moon Tiara Action attack.
Thetis had power over water, demonstrating the ability to manipulate and control the water of the ocean on which the cruise ship was floating: she created several giant columns of water strong enough to punch through the ship's steel frame, and summoned humanoid monsters made of water which, when attacked, would rapidly multiply and increase in size. She could also see things from afar within a water orb and could teleport from place to place through whirlpool gates. She also demonstrated the ability to create illusions, such as when she made a wrecked ship appear to be a luxury cruise liner, and could hover in mid-air and jump very high.
- Thetis' name comes from a sea nymph of Greek mythology; she is also often mistakenly called Tethys, after the sea goddess.