Justin was the highest ranking human to serve The Shadows in the TV series, Babylon 5 who was described to be the show's main antagonist, John Sheridan's opposite and equal. He was portrayed by the late Jeff Corey.
Justin was a self-described "middle-man," likening himself to the people who "draw up the borders, control the currency, decide all the matters that happen transparently around us." After being recruited by the Shadows, he was relocated to Z'ha'dum and coordinated the logistical and practical details of the efforts of the Shadows' human agents. His rank among the human servants of the Shadows was greater than Earth Alliance President Clark's or even Morden's.
Following the Battle of Sector 83, Justin sent Anna Sheridan, who had been "reprogrammed" by the Shadows into a loyal servant, to Babylon 5 to bring back John Sheridan, Justin's "opposite number" leading the Army of Light. The Shadows knew that if they killed Sheridan it would only make him a martyr to his cause, so they hoped to turn him to their own purposes.
He was presumed killed when Sheridan destroyed the Shadow capital on Z'ha'dum by detonating a thermonuclear explosion.