Tetrax Shard

Tetrax's face was the splitting image of Diamondhead's, with the exception of having green eyes instead of yellow, and his diamond skin having a slightly more blue tint. Tetrax wore a shiny grey bodysuit that had a retractable black helmet resembling a pillbug, with a small green triangle visor on the front. Since he never took off the suit, he had no exposed back spikes, and only his head and arms were shown at most. The triangle shape of his visor was also on the center of his utility belt, and there were markings resembling it on either shoulder pad.

Tetrax is a battle-hardened bounty hunter with a strong desire to do what is right. This is partly due to his involvement in the destruction of his home planet, Petropia.

Tetrax claims that he used to be a being who cared about no one but himself and that is what led him to become a mercenary. It was only after Vilgax destroyed Petropia that he realized the effect his actions had on his own people. That experience made Tetrax into the heroic Omnitrix guardian he became.

Upon first discovering that Ben Tennyson has the Omnitrix, he laments the fact that out of the planet's six billion inhabitants, the Omnitrix ended up on the wrist of a child. He also berates Ben's lack of strategy in regards to its use. After helping Ben to defeat the other hunters, during which Ben learns to use the Omnitrix strategically, he decides that the Omnitrix is in good hands, allowing it to remain with Ben.

Tetrax helps Ben become a better hero, teaching him to use the Omnitrix wisely. Ben later repays him by reviving the people of Petropia.