Visas Marr, voiced by Kelly Hu, appears in The Sith Lords. Initially an apprentice of Darth Nihilus, she eventually joins the player's character's party. Visa Marr comes from the planet of Katarr, which was destroyed by Darth Nihilus when she was a child. While she is considered blind, she is able to see through the force which allowed her to find the jedi exile. When she confronts the Exile, she loses and in turn becomes part of the Exile's party. When the Exile confronted Darth Nihilus, they with Mandalore, were able to defeat Nihilus. What happened to her after that is unknown. If she went with the Exile to fight the sith empire or stayed behind is a mystery.
Source: Wikipedia, "List of characters in the Star Wars: Knights of the Old Republic series", available under the CC-BY-SA License.