Luyst Millisor was a Cetagandan ghem-colonel who was assigned by the Celestial Lady Lisbet Degtiar to find escaped telepath Terrence Cee. After the Celestial Lady's death, her successor Rian Degtiar authorized him to pursue Cee out of the Cetagandan Empire. Miles Naismith Vorkosigan eavesdropped on the conversation, and assigned his subordinate Elli Quinn to investigate.
Terrence Cee had contracted with House Bharaputra on Jackson's Whole to create ovarian cultures with the telepath gene and insert them in a shipment heading for the planet Athos. Millisor's team traced him there and killed everybody who had been involved with the project, although Cee evaded them. House Bharaputra sought vengeance on the Cetagandans, and hired Elli Quinn (who was already investigating the Cetagandan team) of the Dendarii Free Mercenary Fleet to hunt down the Cetagandan agents when she showed up to inquire about Cee. After a drawn-out game of cat and mouse, Millisor captured Cee, Quinn, and Athosian doctor Ethan Urquhart on Kline Station. However, he was killed by Bharaputran agents before he could complete his mission.
- Some older versions of Ethan of Athos gave his name as Ruyst Millisor. As a result, The Vorkosigan Companion has two entries for him, one as Luyst and one as Ruyst (the Ruyst one is more detailed).