- Centurion is an automaton from the Marvel Comics UK portion of the Generation One continuity family.
Centurion is a tall blue, gold and silver robot with a cannon originally mounted on his right shoulder but later moved to the left one. Originally he was a mindless robot, designed by humans as a piloted machine to fight the threat the Transformers posed to Earth, but may have later gained sentience.
Marvel Comics UK continuity
Centurion was built by the Intelligence and Information Institute (Triple-I) as a way to battle the Transformers threat. It required a human controller that was linked to the robot remotely from a fortified control room located below Portland, Oregon. Triple-I kidnapped Professor Morris to be the controller because of his experience controlling the Dinobot Swoop.
Centurion was activated ahead of schedule to prevent Joy Meadows from exposing Robot-Master as a fraud and embarrassing Triple-I. Morris was ordered to eliminate Joy using Centurion, but once linked to the control machine Morris forgot his orders and became blinded by battle lust. He attacked Megatron who was also looking to silence Joy.
During the battle Swoop and the Dinobots were able to rescue Joy and Centurion followed them, the sight of Swoop having snapped Morris from his madness. He then helped the Dinobots fend off the Decepticons who were still determined to capture Joy. Abandoned by Triple-I, Morris was left locked in his control room where he swore vengeance on his kidnappers. He then caused Centurion to leave with the Dinobots.
Sometime later Centurion wandered off from the Dinobots to investigate a strange meteorite impact. He discovered Galvatron who had recently traveled back in time to the twentieth century. Galvatron, temporarily disoriented, attacked and destroyed Centurion after mistaking him for Rodimus Prime in his madness.
It is unclear what happened to Centurion and Professor Morris at this point. After being rebuilt Centurion appeared to become sentient and Professor Morris’ fate remained unknown. Simon Furman himself seems unclear on whether Centurion is sentient or not: "We ‘assume’ that's him communicating through Centurion later in ‘Ancient Relics’ (though I confess it's not clear)." 
Feeling guilty that he had been repaired before other more deserving Autobots, Centurion sacrificed himself to stop Megatron from killing Grimlock, Blades and a team from Action Force. He and Megatron ended up fused together at the bottom of the river Thames in London after being engulfed in a massive explosion.
His body was later raised from the Thames along with Megatron's by the human entrepreneur Richard Branson, who was attempting to clean the river in the name of environmentalism (and publicity). The bodies were captured by the Decepticons who wanted to revive Megatron as a weapon against Galvatron. They later separated Megatron from Centurion. His fate is unknown but presumably he was destroyed.