Justin Cranleigh

Justin Cranleigh was a friend of the Winterdawn family. He was Sandra Winterdawn's lover until he was driven mad by Gabriel and Tanith disassembling him and using him as a template to create Harry Truman, then reassembling him.

As he was later dying, the Seventh Doctor was able to get him to use the power of Cathedral to ease the universe's pain, making Gabriel and Tanith mortal and powerless. (PROSE: Falls the Shadow)

Continuity
While reading Charles Moore Wedderburn's The Trail of the Black Orchid: A botanical and zoological guide to the journeys of George Cranleigh, Jeremy Winterdawn wondered if Justin and George were related. (TV: Black Orchid (TV story))