The Marshal enjoyed hunting and killing Solonian mutants. He strongly opposed the Empire's plan to grant Solos its independence, as it would mean an end to his career. He had Varan's son, Vorn, assassinate the administrator sent to grant it, accused Ky, and killed Vorn.
He then attempted to carry out his plan to permanently change the atmosphere of Solos to make it habitable for humans. He was defeated by the Third Doctor, and killed by Ky after he had metamorphosed into an advanced Solonian. (TV: The Mutants)