The Prototype Sentinel was developed by the Hellfire Club when they were operating in San Francisco at the beginning of the 20th century. They used psychics to learn more about the birth of the "Over-Men", the next stage in human development. They designed a weapon they dubbed the Sentinel to help track them down and destroy them if they got out of hand.[1]
When the X-Clubtravelled back in time to collect DNA samples from Doctor Nemesis' parents, arrived they learned after their arrival that Dr. Nicola Bradley and his wife Catherine Price had been working on a new energy source. The Hellfire Club kidnapped them to use this energy source to power their new Sentinel. The X-Club came to their rescue but the battle between the Hellfire Club's Sentinel and the X-Club caused the 1906 San Francisco Earthquake.[1]
