Ravis was an alien who Hoshi Sato met on Risa in 2152. She became intent on learning his language, which was very difficult to master. He attempted to teach his language to her, without much success. Ravis then invited Sato to join him in the exotic steampools of Risa, which she did. In the end, they wound up spending the night together, and Ravis worried that Sato would feel that he took advantage of her. (ENT: "Two Days and Two Nights")