Danton Hyleg served as a mobile suit test pilot for the Principality of Zeon and later Neo Zeon, specializing in developmental data collection. Though his exceptional piloting skills earned widespread acknowledgment, a steadfast refusal to take human life confined him exclusively to testing roles. A superior explicitly cited this limitation as preventing combat deployment, stating it was "unfortunate, given your excellent flying skills." Following the Second Neo Zeon War, Danton concealed his identity and relocated to Side 6 with Arlette Almage, seeking a civilian life away from warfare. In late U.C. 0096, Danton accompanied Arlette as part of an investigative team collaborating with the Earth Federation's Mastema special forces unit, commanded by Lieutenant JG Mehmet Merca. Their mission involved entering the drifting asteroid Axis to address Federation concerns about psycho-frame technology. During this operation, Mastema forces encountered hostility from the RX-78AN-01 Gundam AN-01 "Tristan" and the private militia Birnam. To defend the team, Danton utilized abandoned Neo Zeon mobile suits found within Axis. He piloted the AMX-011S Zaku III Custom – a unit he had helped develop – and later the AMX-104 R-Jarja. His combat actions demonstrated his retained piloting expertise, undertaken while supporting Arlette Almage's separate objective to uncover information about Char Aznable near the wreckage of the Sazabi.