Originating as the Quintessons' Dark Guardian robots, the Guardian robots of the Golden Age of Cybertron were powerful giant blue robots that kept the peace. They gave the Decepticons much trouble during the early days of the war but were eventually overcome.
Only one, Omega Supreme, the Guardian robot of the Crystal City, was ever named, had a distinct color scheme, and was shown to be sentient or able to transform, but it was not revealed if he was indeed unique amongst them in those regards.
At the end of Cybertron's Golden Age, the Guardian robots fought against the newly assembled Decepticon army extensively and destroyed quite a few drone warriors. They gave Skywarp the creeps with Thundercracker stating that they gave them a "pounding" in the old days. Shortly before Megatron's first confrontation with the newly activated Optimus Prime, a Guardian's head was destroyed by Decepticon laser fire, deactivating it.
Millions of years later, after escaping an Autobot attack on their time machine facility, the Decepticons found the remains of the damaged Guardian robot. Shockwave managed to reassemble the giant, though he noted that the lack of a head would limit its maneuverability, to which Megatron commented that "A warrior doesn't need a head, just a good strong body."
This Guardian was unleashed upon Optimus Prime and the Autobots until the Aerialbots arrived from the past and merged into Superion. The sheer strength of the Guardian overwhelmed Superion at first, but he retaliated to such an extent that the Guardian was thrown into the air before crashing back into the ground where its body was destroyed.
At a pivotal point in Cybertron's history, the young Optimus Prime managed to defeat the Decepticon Leader Megatron in single combat. Without a strong leader to unify them, the remaining Decepticons quickly turned on each other, breaking into small warring bands. Now, only Polyhex remains as a bastion for the Decepticons. Cybertron is relatively peaceful, and due to Autobot explorations, the planet is once again rich with Energon. Guardians keep the peace, and from the outside, things look perfect - at least, in Iacon.
Since the Guardians pre-date the invention of transformation, they are not Transformers, aside from the rare exception that got upgraded later.
In the Shattered Glass universe, Dark Guardians were also oppressors in ancient times, but then helped keep the peace for countless eons. When Optimus Prime launched his war on Cybertron, Alpha Trion took out most of the remaining Guardians with his Coda Remote. Two of them -- Broadside and Omega Doom -- joined the Autobots. Most of the rest were destroyed and their parts recycled for the war effort.
| This page uses content from Teletraan I: The Transformers Wiki. The original article was at Guardian robot.