Doku was a heavy mobile mecha designer, and offered his services to Harulu. He believed his experience with mecha would enable him to capture the Ideon. His initial strategy was sound, as his forces were able to separate and disable the Ideo-Delta, and only the timely arrival of the other Ideon units prevented him from capturing it. However, an attempt to follow this with a raid on Brazillier was undone when the Ideon unleashed its' All-Directional Missile Attack and wiped out the majority of his unit.
Doku then opted for a more straightforward approach, using a false radio transmission to lure a group of colonists away from the Solo Ship on a Karioka shuttle, then taking them as hostages. He set up an exchange, planning to swap the hostages for the Ideon jets. However, the Ideon crew duped him (rather easily, it must be said) and unleashed the robot on his forces once the hostages were safe. Doku was then killed when his Zigg Mack mecha was destroyed by the Ideon.