Some time after this Shaw appears at a Hellfire Club dinner hosted by Sunspot and is alerted to a device left to him by his father exploding elsewhere in the compound resulting in the insanity of two club menials and Shaw asking his manservant for a file labelled "Kronos". After being upbraided over the explosion and deaths by da Costa he is ordered to investigate. Shaw however knows the cause. The explosion in the Hellfire Club was caused by the activation of a machine developed beneath the Alamogordo genetics plant in Las Cruces, New Mexico by Mister Sinister. In the past Sinister had worked here (disguised as a Dr. Milbury) alongside Brian Xavier, Kurt Marko and Irene Adler who had been gathered for him by Jacob Shaw, Sebastian's father, as they all had the X-gene and Sinister predicted their children would be mutants. Sinister then experimented of these children (including Cain Marko, Charles Xavier and Sebastian himself), imprinting himself on their DNA. Sinister's machine, dubbed the Cronus device, was designed to activate soon after his death and would activate these hidden copies until Sinister could be reborn in one of them. Jacob, wanting to protect his son, created the device in the Hellfire Club from Sinister's notes to alert and protect Sebastian from the Cronus device. Shaw travelled to New Mexico to visit another of the children to confirm his theory, running into Xavier and Gambit who were investigating a hit list with the children's names on it. Following them he is present when they are attacked by mercenaries under the employ of Amanda Mueller, a former associate of Sinister's. Xavier is captured and Gambit and Shaw team up to save Xavier. It is revealed that Mueller wants to house the powers (though not the personality) of Sinister herself and so is assassinating the children, having undergone the procedure herself. She shoots Xavier, who is already struggling to stop Sinister from taking over his body, which allows him to take over. Sinister in Xavier's body stops Mueller but is in turn confronted by Shaw and Gambit who destroy the Cronus device while Xavier casts Sinister out of his mind. With the threat gone, Shaw leaves.