Tressa was a Drayan who appeared to be a child but was actually an elderly woman at the end of her life, reaching her final days in reverse.
Tressa belonged to the Drayans, a reclusive people who age backward, becoming childlike as they near death. Drayans at the end of life were taken to a sacred moon to die, but Tressa and two companions fled their caretakers.
In Innocence, Tuvok crash-landed on the moon and found Tressa, Elani and Corin, believing them to be children whose ship had crashed. Protective and patient, he hid them from the Drayan search party. When the others vanished, Tuvok learned the truth from First Prelate Alcia. Tressa came to understand her own fate, and Tuvok stayed with her until the end.