Oddly Obsidian's tech specs have little or nothing to do with the character as seen on the show, instead being described as a simple drone-general attaché.
His biography indicates that he provide air support for Vehicon Tank-Drones, but oddly portrayed him as made to be a fairly mindless air-attack unit by Megatron, which contradicted his show history as a Cybertronian General.
The appearance of Obsidian is based on concept art provided to Hasbro by Draxhall Jump.
They first appeared in the episode "Sparkwar Part 1", where they immediately made an impact. Pretending to be dim and fairly weak, a'la Tankor, the two lured the Maximals into a trap, cutting off their every option with countless numbers of new Vehicon Drones. Cornering them underground, the Maximals only escaped due to Botanica's intervention.
Unlike the previous generation of Vehicon generals (Tankor, Jetstorm and Thrust), both Obsidian and Strika weren't given alternate personalities. They remained who they had always been. However, their prime directive was the protection of Cybertron, and they had been programmed to perceive Megatron and Cybertron as one and the same. To defend one was to defend the other. Unlike the previous Generals, Obsidian was willing to take the responsibilities of his own failures, making him perhaps the most honest of the Vehicon Generals. Obsidian and Strika were the first vehicons to address Megatron as "Lord Megatron"
Obsidian proved himself to be a tactical genius on the battlefield, given his past history as a supreme general. Despite his military brilliance, he was at a loss when without a certain directive. When Megatron was seemingly destroyed, he and Strika joined the Maximals, since their options had become limited. This alliance would turn out brief though, for when Megatron returned in the body of a Diagnostic Drone, Obsidian and Strika immediately return to his side.
In the final battle with the Maximals, Obsidian and Strika were tricked into standing on an antigravity unit by Cheetor, who launched the pair into space, where neither were affected by the reformatting of Cybertron.
According to an F.A.Q. on Bob Skir's web site there was a scene with Obsidian and Strika cut from the final episode. "Obsidian and Strika had a MAGNIFICENT scene in which they return to Cybertron and decline an offer to be reformatted themselves (partly because they feel unworthy because of their role helping Megatron, and party because I wanted them to remain "pure" when I brought them back in the next series... which (as of this writing) I haven't been invited onto yet. Sadly, their finale got cut for time."
His bio indicated he that similar to the real Obsidian, had previously been a great general, captured and turned into a Vehicon by Megatron. Unlike the Obsidian from Beast Machines however, this Obsidian secretly plotted to overthrow his master. Lacking Strika in this universe and recognizing his own shortcomings, he teamed up with Tankor, who had not regained his Rhinox memories. Together they overthrew Megatron, taking control of Cybertron for themselves. Recognizing his leadership abilities, Unicron plucked him (along with Tankor) from his universe and made him one of his troops.