Episode 30 of The Trigan Empire
The Prisoner of Zerss
aka The Worst Man on the Planet
The Great Reign of Terror
De gevangene van Zerss (Dutch title)
The Prisoner Of Zerss (Dutch title, translated)
The Prisoner of Zerss was originally published in 10 installments in issues 517 (11 December 1971) to 526 (12 February 1972) of Look and Learn magazine.
It is reprinted in the Don Lawrence Collection Volume 8, The Prisoner of Zerss.
523 (22 January 1972)
524 (29 January 1972)
525 (5 February 1972)
Plot summary (Dutch)