Trant appears for the first time after the Wing Zero is abandoned by Heero and Quatre. Though ordered by Tubarov to destroy the Gundam to erase all evidence of its existence, Clark felt that the Gundam's ZERO System is the key to turning the tide in the war, especially to render the mobile dolls obsolete and works independently to understand it. His troops capture Heero, Quatre, the Gundam scientists and soldiers of the Treize Faction. He had the former test out the system, determining that it can fight even more efficiently than a mobile doll. Unfortunately, Heero took control of the Gundam and went berserk, trying to kill anyone trying to kill him. Eventually, it was abandoned and Clark attempted to pick up the pieces. He continued to use the Gundam to record results but the complexities make it hard for him after prolonged periods of use. After it is discovered that he used numerous mobile dolls to gather data on the system's capabilities, Tubarov sends a number of soldiers to discover his whereabouts.
During the same time, Trant tracks down Gundam pilot Duo Maxwell and forces him to battle the mobile dolls in order to gather more accurate data. Duo becomes overwhelmed by the ZERO System and is pulled out of the cockpit by Trant as OZ soldiers arrive to retrieve Trant and destroy Wing Zero. Trant immediately pilots Wing Zero and easily dispatches the soldiers and their accompanying mobile dolls. However, the ZERO System overwhelms his mental state, making him crave more destruction. Duo, now piloting his Deathscythe Hell, prevents Trant from destroying a nearby colony and eventually kills him in battle when their attacks collide.
In the Glory of Losers manga, Trant Clark gets killed when he self-destructs the Wing Gundam Proto Zero as he loses his mind from the ZERO System during the battle with the Deathscythe Hell.