Obtained: Speak with Eighter in the North Mountain Area after the main story 17, 18, and… 16?!
Objective: Defeat all the poacher’s hunter robots
After the events of 17, 18, and… 16 ?!, you will gain control of Trunks. Head over Android 8 near the center of the map and speak with him. Following the cutscene, head to the sub story markers on the east and southwest parts of the map to defeat the poacher’s hunter robots. When both groups are defeated, return to Eigther and speak with him to complete the story.