Samurai Destroyer
The robot that was eventually called the Samurai Destroyer was a fourth robot being constructed by the Followers of the Light who had armed the Shogun Warriors with the mechs they needed to battle their for Maur-Kon. However, the Followers were slain and their Sanctuary of Light was destroyed before they could be finished. The Shogun Warriors then buried the Followers and abandoned the Sanctuary unaware that this fourth robot was being built. The robot was found by adventurer William McLaughlin who salvaged the Follower's computers and learned of their time on Earth and used spare parts to complete the robot that he called the Samurai Destroyer.
McLaughlin then decided to use the Destroyer for his own personal gain, first destroying the other robots piloted by the Shogun Warriors, then committing a series of robberies then stashing his stolen loot at the Sanctuary ruins. Eventually, the Shogun Warriors and the Fantastic Four caught up with McLaughlin and his robot. In the ensuing battle the Samurai Destroyer was destroyed, and McLaughlin turned over to the authorities.