After entering the cockpit, a devilish smile appeared on Nico's face. She turned around and punched the Fourth Master's body.
The willpower magnetic field on the Sixth Master's body blocked several of Nico's attacks. However, the two of them were in the cockpit of the mecha, so he could not escape. After being attacked by Nico a few more times, he was killed with a single punch.
After killing the Fourth Master, Nico's figure began to change, turning into Ning Shi's appearance.
It turned out that Nico was Ning Shi.
After Ning Shi came to Taining Planet, he activated the synchronization between his main body and his avatar. The avatar had the main body's transformation ability.
Ning Shi had Nico disappear on her own accord while he transformed into Nico. He had used the gap in the past between the masters and the greed in their hearts to design this conspiracy.