- "Fear—A Jedi spends his whole life training against it. But at the Citadel, breaking Jedi is our specialty. Within these walls they will learn to fear us. If not, they die."
- ―Sobeck on his prison detail, specifically Jedi.
Osi Sobeck was a Phindian Separatist during the Clone Wars who served as warden of the Citadel Facility on Lola Sayu and was considered ruthless and sadistic by his prisoners, earning a frightening reputation with the Republic.
During the second year of the war, Sobeck was charged with extracting crucial information Even Piell, Wilhuff Tarkin and several clone troopers. Due to the loss of Piell, a highly respected Jedi General and member of the high council with vital hyperspace lane coordinates, Obi-Wan Kenobi, Anakin Skywalker, Echo and Fives, Rex and Cody used carbonite freezing in a plot to infiltrate his base. While caught up in the act, Even Piell and Wilhuff Tarkin broke out, forcing Sobeck to take action. He activated an electrified wall running disc, killing one of the clones and sent out a group of modified BX Droid Commandos to kill the rest, though it was in vain and the strike team escaped the Citadel. Sobeck was then contacted by Count Dooku himself, who seemed impatient towards the Phindian. Sobeck demanded more time, and sent out a large group of droids after the escapees and intrapped the group's ship. Half of the group was captured, leading Osi to execute one of the Clones. The group later escaped but was cornered, leading in the presumed death of Echo and the destruction of their ship. Anakin and Obi-Wan then called the Jedi Council for help, causing Saesee Tiin and a large attack force to ascend on the Citadel, causing a major battle to take place. During this battle, Sobeck sent several Anooba out to intercept the group, leading in the death of Even Piell, the prisoner he wanted alive. Enrage, he engaged clones in an open caldera, leading a STAP riding group of battle droids into battle.