Marwood was a member of the Knights Templar.
He inherited a number of treasures from the Templars, including the Imagineum. He lost it in a game of canasta to the Celestial Toymaker. He also began to work for the Toymaker at that time. When his adjutant Felix stole a crucial component of the Imagineum, Marwood tried to retrieve it. When the knight became tired of being the Toymaker's plaything, Marwood tried to kill him but was killed instead. (COMIC: Endgame)
After the Toymaker was defeated, the Eighth Doctor and Izzy Sinclair met Marwood's grandfather on an Indian Ocean island in 1939. (COMIC: Tooth and Claw)