In the past, the town of Siddon was in poor condition until some residents found the remains of a damaged Sentinel who made believe them he was their benefactor and which the mutants were the cause of the misfortunes of their town, and since he was not able to eliminate them because of the damage he had suffered, he persuaded the people to do it for him.
The Sentinel was called Overseer and Dr. Bob Cord, and before him his father and grandfather, was the faithful stewards which saw to the elimination of the mutants until to Siddon came Cerebra which made open the eyes of the citizens of Siddon about the true nature of Overseer, which in the meantime the its self-repair program had made him to operate again. However Cerebra and the citizens of Siddon together managed to defeat and destroy the Sentinel.
Powers and Abilities
Presumably conventional Sentinel weaponry.