While a child, he created a conceptual space with his mind, containing every possible book that could ever be written. However, many of these books were of poor quality, such as a set of books featuring variations of "A man walked down a street" and basic descriptions of the man.
By the 1890s he was infirm, but had made a younger avatar of himself. He targeted creative homosexual men, bringing them to his house and draining their imagination to feed his library. Sergeant Percival Quick and George Litefoot grew suspicious at the mysterious deaths of otherwise healthy young men and began to investigate what happened to a poet named Ambrose Hutchinson. Hardwick and Kempston persuaded him to go after Oscar Wilde, so the temporal disruption caused by the writer's premature death would bring Claudius Dark into the open. However, Leela, Henry Gordon Jago and George Litefoot were able to stop Gadd without Dark's help, with Wilde's dismissal of Gadd's fixation on beauty over life disrupting his powers at a point when he was already weak. He was last shown trying to hold back a bullet that had been fired at his true while his library collapsed around him, leaving him in a position where he would either be shot or crushed. (AUDIO: Beautiful Things)