Centurions are the giant, armored law enforcement robots that patrol the streets of Iron City in the film Alita: Battle Angel. Their primary function is to maintain public order, and they are a constant, towering presence throughout the city's alleyways and thoroughfares. They are seen tirelessly monitoring the populace for any signs of danger or suspicious behavior. Part of their duty includes ensuring that the city's bounty hunters, known as Hunter-Warriors, adhere to their designated code of conduct.

In addition to street patrols, Centurions are responsible for guarding critical infrastructure, such as the Factory that serves as a processing hub for Hunter-Warrior bounties. They also play a key role in upholding the absolute law forbidding anyone from the surface to ascend to the floating sky city of Zalem, keeping the area under constant observation. Their imposing physical presence is sufficient to intimidate most citizens; for instance, one citizen instinctively protects a dog from being crushed underfoot by a Centurion, highlighting the danger these massive machines pose to everyday life in the city. Beyond these functional roles and physical descriptions, no reliable direct information exists regarding the Centurion's personality, motivations, character development, key relationships, or specific notable abilities.