Robian is the term applied to roboticized Mobians. The Robians acted as the primary labor force for Dr. Ivo Robotnik in Robotropolis and in various territories across Mobius. Though generally lacking free will, Dr. Robotnik occasionally reprogrammed them to give them some free-thinking capabilities, which often resulted in their true memories becoming distorted. After Robotnik's death, the Robians within Robotropolis regained their free will (a side-effect from the Ultimate Annihilator) and wanted to separate from the main Mobian population and have their own home in Knothole, feeling that they would never be accepted back into the normal population. Distrust, paranoia, and a law declaring the dismantlement of all Robians by King Max (whose was influenced and controlled by Ixis Naugus at the time) led to civil war. Eventually, thanks to the Knothole Freedom Fighters' intervention between on both sides and rescuing the king, the war came to a miraculously short end with no casualties, and the Mobians and Robians learned to live together in peace. (SSS: #2, #4)

During Sonic and Tails' quest to track down Ixis Naugus, they encountered Robians in the Kingdom of Mercia, Sand Blast City and the Great Rainforest that were still under the late Robotnik's influence. While the Robians of Mercia remained under the control of the High Sheriff, the Robians in the latter two regions had no commander, but wandered around aimlessly in hordes firing at anyone that strayed into their path with their opti-burst arrays. When Dr. Eggman took over Dr. Robotnik's position, all the Robians were all bent to his will, and increased in number after the Shadowbots invaded Knothole. Many of the Robians living in Robotropolis had their free will restored by the Sword of Acorns, though others around the globe remained Eggman's mindless servants. (StH: #58, #62, #63, #100)

In 3236, the Bem reversed the roboticization effect on everyone else except for Jules Hedgehog, Bunnie Rabbot, and a group of Dragons, who were deep beneath the planet's surface and thus remained roboticized. Bunnie was unaffected because she had previously had her roboticized limbs replaced with regular cybernetics for health reasons, while Jules's old Great War injuries would be restored and kill him if he was ever de-roboticized. As a plus, Eggman was unable to re-roboticize any other former Robians. (StH: #123, 134, #155, #156, SSS: #11)

However, Beauregard Rabbot stated that the Sand-Blasters didn't trust the former Robians and treated them as second-class citizens, driving them into the badlands. Wanting to protect his group, Beauregard was forced to approach the Eggman Empire for help; the former Robians received cybernetic upgrades and joined the Dark Egg Legion, forming the Great Desert branch. (StH: #217)

When Eggman reset the universe in Operation: Clean Sweep with his new weapon, the Death Egg Mark 2, the process nullified the worldwide immunity to Roboticization. When it was revealed that Eggman's new weapon had the ability to roboticize the whole planet, Sally sacrificed herself by ordering Nicole to direct the beam on her, thus turning her into Mecha Sally while leaving the rest of the world unscathed. Eggman later discovered that Operation Clean Sweep only left 50% of the Mobian population vulnerable to roboticization again. (StH: #230, #236)