Sebastian Shaw was born in Pittsburgh, Pennsylvania. His powers manifested shortly after he was accepted into the engineering college (probably Carnegie Mellon University) and his father, Jacob Shaw, died of an incurable disease. He endeavored to finish his studies and then create the Shaw Industries, a multinational corporation that was heavily involved in contracts with the Department of Defense of the United States and in the manufacture of ammunition, building a multimillion-dollar empire at the age of 40 years.

Hellfire Club
Shaw was promised in marriage to Lourdes Chantel, also a mutant, and immediately joined the Hellfire Club, due to his immense fortune, along with Warren Worthington Jr. (father of Archangel), Howard Stark (father of Iron Man) and Sir James Braddock (father of Captain Britain and Psylocke), drawing the attention of the White King of the Inner Circle, Sir Edward "Ned" Buckman. Shaw aspired to become the absolute leader of the Inner Circle for his own purposes, and quickly began looking for other allies, also mutants to annex them to the Circle. Upon discovering who was behind the Project: Armageddon and the Sentinels was Ned Buckman, he used the telepathic powers of Emma Frost to manipulate him, causing him to liquidate all the members of the Selection Board including the White Queen of Ned, Paris Seville, and after committing suicide. However, in the conflict, Lourdes, Shaw's lover, perished.4 Sebastian proclaimed himself Rey Negro and changed the name of the Selection Council to that of the Inner Circle, in which he included Emma Frost, Harry Leland and Donald Pierce. , a cyborg, like Lords Cardinal of the Hellfire Club. Next to Shaw was his assistant Tessa (Sage), who worked undercover for Charles Xavier.5

Black King
As leader of the Hellfire Club, Shaw began working on his plans for world domination through force, money and authority. Friendships with high official and governmental positions elevated him in power, making him a tenacious enemy. It has also cooperated with the covert project of the United States Government known as Project: Wideawake, which was emerging as the solution to the growing problem posed by the increasing appearance of mutants in the country. The Shaw Industries have secretly manufactured Sentinels for this project, claiming that it was always better to have control over them. Because of this, he met people related to the Project: Wideawake, Senator Robert Kelly and Henry Peter Gyrich, an anti-mutant.

Shaw was one of those who tried to influence the X-men Jean Gray (recreated at that time by the Phoenix Force), upsetting his mind and turning it into Dark Phoenix). All this led to the first battle of the Club and Shaw against the X-Men.6

Later, the Hellfire Club and the X-men joined forces to fight the Super-Sentinel of the future known as Nimrod. In that battle, Harry Leland perished, and Shaw invited Magneto, at that time, member of the X-men, to become the new White King of the Club.7 Magneto accepted the offer.8

Time later, Magneto began to promote the expulsion of Shaw of the Internal Circle. Magneto was supported by Emma Frost and Selene, the Black Queen. Shaw was expelled and Magneto was proclaimed as Gray King (combination of White King and Black King).