Magnus Greel
Magnus Greel was an the Minister of Justice for the Supreme Alliance in the 51st century, an era in which Humans had just begun to discover how to travel through time. A war criminal, he escaped in a time cabinet to the late 19th century China and then to London, where he continued his depraved activities on a smaller scale.
Profile
During Greel's time an Ice Age had fallen over Earth and split the population into a number of warring Alliances. The Icelandic Alliance and Greel's Supreme Alliance were at war. The Islandic Alliance fell when Greel had the doll-like but homicidial cyborg known as the Peking Homunculus assassinate its commissioner, an event which nearly precipitated a sixth World War. As the Supreme Alliance's ironically named Minister of Justice, Greel carried out an atrocity earning him the title of the "Butcher of Brisbane". Greel would massacre 100,000 souls, all told. (DW: The Talons of Weng-Chiang) A Human monster, Greel would think nothing of unprovoked murder and cannibalism (DWM: Under Reykjavik).
After the defeat of the Supreme Alliance in the Battle of Reykjavik, Greel used a time travel process utilizing a cabinet-sized time vessel and zygma beam energy to travel back in time to the 19th century China with the Peking Homunculus. Greel passed himself off as a god, Weng-Chiang, to a lackey, Li H'sen Chang, and, with Chang posing as a conjurer and the Homunculus as Mr Sin, a ventriloquist's dummy, eventually found themselves in London.
The passage through time had caused great damage to Greel's DNA, deforming him. He work a mask and concealing clothes to hide his true form. While Greel lived in fear of Time Agents, Chang abducted young women for him so that he might use their life energy to restore himself, a method which did not really work and only caused the damage to accelerate. The Doctor and Leela eventually caught up with him and subjected him to the same process, which destroyed his body entirely, killing him. (DW: The Talons of Weng-Chiang)
