SEBASTIAN SHAW

Sebastian Shaw's father Jacob was a poor relation in 1915 London, envious of his older brother Esau and of the Hellfire Club seat their late father had held. Nathaniel Essex — Mister Sinister — offered Jacob a way up: gene work that gave him unstable shapeshifting powers. Jacob used those powers to impersonate Sir Waltham Pierce and murder Esau, then fled England when the killing went wrong.

Jacob then spent decades working for Sinister in America, hunting down carriers of the X-gene for his employer's experiments. What Jacob learned late was the price of the bargain: Sinister had encoded a copy of his own essence into the DNA of several children of those carriers — Charles Xavier among them, and Jacob's own son Sebastian. Sinister's Cronus device was built to wake that copy after his death and let him be reborn inside whichever host answered first.

Jacob stole Sinister's notes and reverse-engineered a counter-device of his own, a machine that would shield Sebastian from the Cronus signal as long as it stayed near him and active. He pressed it on his son with a single instruction: always keep it close. Sebastian Shaw, a man who trusts no one, has carried his dead father's protection ever since — the one debt the Black King never chose to owe.