Doctor Augustus Julius Sinister IV is a 37 year old evil genius intent on absolute universal domination. Part-man, part-machine, part LEGO (he swallowed a small piece as a child), he somehow manages to occupy the same brain as his more down-to-Earth alter ego, Andrew Summersgill, although it's getting a bit fraught in there and the legroom leaves much to be desired.
Both Andrew and his evil counterpart are LEGO obsessed and between them they have a permanent LEGO town (Tabletown) in their garage which is used as a testbed for future world domination experiments. The space beneath Tabletown is also a good place to hide from local law enforcement authorities when they come to pay a visit.
With an unending series of clones to replace him, Doctor Sinister is seemingly immortal and invincible - his one weakness being his penchant for cloning genetically modified and cybernetically enhanced Allosaurs as "pets". Rumour has it that an accident with one of these creatures is the cause of his cybernetic eye and robotic arm, but such stories are strenuously denied - on pain of death.
Doctor Sinister's LEGO creations can be found on Flickr.