Originating as the diminutive Cybertronian Ros, he fled Cybertron four million years ago aboard a refugee vessel with Fortress. Their crash landing on the hostile planet Master forced survivors to develop lifeless transtector bodies for survival. Ros underwent rigorous mental and physical conditioning to master transformation into a head module, becoming a Headmaster bonded to a larger transtector form collectively designated Hardhead. This process unlocked latent psychic powers like telepathy and telekinesis among the Headmasters. His personality centers on stubbornly unwavering military discipline. He typically rejects advice unless manipulated into believing it was his own idea, communicates bluntly with minimal words, and prioritizes combat efficiency over social niceties. Despite this rigidity, he forges a remarkably effective binary bond with his Nebulan partner Duros, sharing an enthusiasm for warfare. Their compatibility is noted as potentially the strongest among all Autobot-Nebulan partnerships. Functionally specializing in ground assault, Hardhead transforms into a Cybertronian tank armed with a 120mm laser-guided cannon firing incendiary, sonic, and explosive shells, reaching 155 mph with a 450-mile range. His robot mode wields dual shatterblasters firing diamond-hard crystal shards capable of shredding thick steel. His design offers resilience against most artillery and energy weapons, though weapon recoil often causes internal damage. Exhaust gases from his tank mode can melt surfaces of pursuing entities. Within Japanese continuity, Hardhead returns to Cybertron in 2011 aboard Fortress Maximus's ship to counter Galvatron's rebel Headmaster-augmented forces. He engages in numerous battles, confronting Sixshot and undertaking missions to planets like Beast and Mars. He notably employs the "Cross-Head" technique with fellow Autobot Headmasters to escape Decepticon traps, drawing on their shared survival training from Master. His tactical approach often involves direct, head-on assaults with minimal strategy. In American cartoon continuity, caught in an energy surge during a battle over the Plasma Energy Chamber key, he crash-lands on Nebulos. Captured by rebels, he volunteers for the Headmaster process, bonding with Duros. Together they fight Hive rulers and later Decepticons under Scorponok, participate in retrieving the key, and witness Cybertron's rebirth. He subsequently remains on Nebulos to aid reconstruction. Marvel Comics depict him serving under Fortress Maximus, initially deactivating by surrendering his head as a peace gesture to Nebulans. Reactivated and binary-bonded to Duros during a Decepticon attack, he later relocates to Earth. Key actions include rescuing captive Targetmasters by defeating Weirdwolf and Skullcruncher, and participating in the defense against Unicron where he is apparently crushed while deploying artillery. IDW Publishing portrays him as a career soldier grappling with existential uncertainty about his purpose beyond war. During the Brasnya conflict, he reinforces Optimus Prime's unit and later accompanies Nightbeat to investigate Gorlam Prime. After Nightbeat falls under Jhiaxus's control and attacks him, Hardhead survives a point-blank shot due to his durability, eliminates the compromised Nightbeat, and enters a Dead Universe portal. He reemerges transformed with grey coloration, blocks Jhiaxus's escape, and reveals his new connection to the Dead Universe's energies.