Darth Altous, born Yisoo-Zaar, was a Draethos Sith within the Kroprulan Empire. Yisoo-Zaar was part of the Jedi Order from when he was born to 19 BBY until he was turned to the dark side and joined the Kroprulan Sith Empire. During his time as a Jedi, he participated in all the major wars that shaped the galaxy such as the Clone Wars and the Galactic Civil War. He participated in the Darth Dude Conflict as well.
Altous was one of the most respected Sith within the Empire even being admired by the Empress herself. He was known to be wise and having an intelligent mind. His experience in the Force allowed him to be a Prophet and be able to look deep into the Force. He was known to be a mentor of Darth Matas and his son Sirak Kolar.