Gibbis

Gibbis was a native of Tivoli, a grey planet whose residents took a strange delight in subjugation. Although they feared death, they welcomed invasion and Gibbis' old school motto, resistance is exhausting, sufficiently reflected this mindset.

He was a coward. The Doctor understood Gibbis' cowardice immediately, recognising that it was one of the reasons that Tivoli's civilisation had survived; it was an aggressive sort of timidity. Gibbis was prepared to sacrifice Howie in the name of self-protection and showed a sadistic pleasure in unnerving Amy when he suggested she might have not yet have entered 'her room'.

Before he was plucked from Tivoli and locked into the Minotaur's prison, Gibbis worked in town planning. He was engaged in a project to line all his planet's highways with trees so that invading armies could march in the shade. (DW: The God Complex)