Gang Lei gradually grew tired of the war. Promises of wealth and conquest by Darth Sidious, the secret patron of the Separatists, could not assuage Gunray's desire for peace. He questions General Grievous's leadership and even risks angering the cyborg general.

Three years later, when the separatist forces were retreating, Darth Sidious asked General Grievous to send the separatist leaders, including Newt Gundray, to the planet Mustafar. , saying it was to protect them, but at this time these people actually had no effect on him at all. When Sidious conquered Anakin, the second order he gave him (by this time he was named Darth Vader) was to go to the planet Mustafar and eliminate all the leaders of the separatist forces. When Vader arrived on Mustafar, Newt Gundray and others gave him a heartfelt welcome. However, Vader started killing as soon as he closed the door, and everyone (including the battle robots present) was not spared. When Gang Rui was finally left, he was still saying, "He promised to give us safety!" But this sentence did not save his life in the end.