Tesuni was a Youma owned by Nephrite.
Her essence was implanted into the tennis racquet of Rui Saionji as part of Nephrite's plan to gather energy for the Dark Kingdom Once Rui reached her maximum energy potential, Tesuni appeared from the racquet and drained her of her energy. When Sailor Moon arrived to help the girl, Tesuni trapped her inside a giant tennis ball. Tuxedo Mask arrived and distracted the Youma by striking her with his cane, which allowed Sailor Moon to free herself.
Tesuni attempted to attack again, but Tuxedo Mask threw a rose which struck the Youma in the face. Sailor Moon took advantage of the opportunity and destroyed Tesuni with Moon Tiara Action.
- Tesuni’s name is a pun on the term テニス tenisu which is the Japanese spelling of the English word tennis.
- Tesuni appears as a common enemy in Sailor Moon: Another Story.
- Tesuni is the first Youma to possess an object, as oppose to previous Youma who took on a human alias to steal energy.