Shinobi Shaw is the illegitimate son of Sebastian Shaw. Rejected and abandoned by his father at an early age, Shinobi grew tired of waiting to inherit his father's wealth and wearied of the elder Shaw's contempt for his decadent lifestyle. When his own mutant powers manifested after puberty, he discovered they closely resembled those of his "uncle," Harry Leland. Believing himself to be Leland's son rather than Shaw's, the last vestiges of Shinobi's loyalty to Sebastian Shaw vanished. He soon became involved with the mysterious group of hedonists and power-seekers known as the Upstarts.
Using his own business skills, Shinobi amassed a private fortune of his own and bought out Shaw Industries from under his father's feet. Confronting Sebastian Shaw with this coup at his father’s retreat in Interlaken, Switzerland, Shinobi drove his father into a rage before using his mutant abilities to slay his father. Taking Shaw's ring as the symbol of his victory, he announced his triumph and claimed his father's place as Black King of the Inner Circle of the Hellfire Club.
Shinobi quickly took control of Shaw's resources, and began assembling a personal guard of Sentinel-class robots and mercenaries. But Shinobi soon found himself in a deadly game with another rival for control of the club, fellow Upstart and mutant, Trevor Fitzroy. With his own Sentinels, Fitzroy separately defeated Inner Circle members Donald Pierce, Emma Frost, and finally Shinobi himself. Shinobi suffered the humiliation of having Fitzroy cut Shaw's ring from his finger and was left to bleed to death. But Shinobi's personal Sentinels reached him more swiftly than Fitzroy had expected, and they acted quickly to reattach the finger. The operation was successful, although Shinobi still feels a little stiffness.
Marshaling his organization's power, Shinobi prepared for vengeance against Fitzroy, who was later confronted and forced to flee by the X-Men and their ally, Bishop. Shinobi sent his men to Fitzroy's hideout, secretly mined the base with powerful explosive charges, and placed Fitzroy under surveillance.
When the X-Men and Bishop soon attacked Fitzroy's lair, the X-Men tried to retrieve Jean Grey, whom Fitzroy had captured while Bishop was in pursuit of mutant criminals entering our reality through Fitzroy's time-portal. Fitzroy tried to escape when he realized he was outmatched, but Shinobi's minions were waiting and they took Fitzroy captive. Shinobi retrieved his father's ring, then ordered the explosives detonated to kill the X-Men and destroy Fitzroy's base, although everyone escaped the blast.
Shinobi continued to engage in frequent violent conflicts with other superhumans, but this ultimately resulted in his failure to establish himself as his father's successor. Once he learned that his father was alive, Shinobi, presumably in fear of retaliation for his assassination attempt, deserted all of his inherited positions and returned to a more secretive mode of life.