Lukas (Regenerators' timeline)

In an alternate timeline, Lukastopherax, (AUDIO: Extermination) commonly known as Lukas was a Chancellery Guard assigned by Slyne to protect Romana from assassination attempts.

He later took Jonias to see Romana II and Narvin. Lukas suggested that Hector's group were terrorists and wanted to send a squad over to them to stop them from leaving. (AUDIO: Evolution) He helped the Chancellery Guard to reclaim Lord Zakar from the freed slaves who had captured him in order to place him on trial for murder. He tried to stop Science Minister Kavil from entering the Panopticon on urgent business. (AUDIO: Arbitration) When the Daleks invaded Gallifrey, he was ordered to protect Romana and remove her from the Panopticon. Assuming that Slyne was dead, he led her to safety away from the Daleks and later took Romana, Leela and Narvin to the armoury to find some weapons that could defeat the Daleks. He was exterminated by the Daleks when they entered the armoury. (AUDIO: Extermination)

Behind the scenes
Although his full name, Lukastopherax, comes from the Big Finish Productions audio stories Extermination and Intervention Earth, its spelling is pure conjecture.