When the X-Men force the combined Master Mold and Nimrod through the Siege Perilous, a humanoid-Sentinel hybrid emerges from the other side. Raised by a human, Sebastian Gilberti learns of the mutant threat through the media, which touches the hidden memories of his predecessors’ directives, and he grows to hate mutants.
As Bastion, he enacts Operation: Zero Tolerance. Though captured and destroyed many times over, Bastion often returns with a new murderous plan.
Human-Sentinel Hybrid
Bastion is “born” when the giant robotic Sentinel Master Mold—having absorbed the advanced Sentinel prototype Nimrod into its systems—fights the X-Men, who see no other way to stop the virtually indestructible amalgam except to force it through the Siege Perilous, a pan-dimensional portal, which subjects those who pass through to the judgment of the universe’s higher powers. Reemerging from the portal as an amnesiac human-Sentinel hybrid with a seemingly immortal essence, Bastion’s prime directives are soon reawakened, and he begins assembling the international anti-mutant strike force Operation: Zero Tolerance (OZT).
Cybernetics
Made up of cybernetics, Bastion possesses enhanced strength, speed, and endurance. With Nimrod’s body, he can fly via boot jets or wings, fire concussive or disintegration wrist-blasts, and proves immune to telepathic probes. He can to self repair after a blast nearly tears through him. He can time travel and create portals.
As a by-product of the Siege Perilous’ magic, Bastion’s essence is seemingly immortal.
Like his predecessor Master Mold, Bastion is able to create other Sentinels, including Prime Sentinels.
Mutant Prey
Bastion often battles the X-Men and the team routinely defeats him. He also faces the robot soldier X-51/Aaron Stack, AKA Machine Man, and the time-traveling cybernetically-enhanced mutant Nathan Summers, AKA Cable.
Allies in Arms
The anti-mutant crusader Reverend William Stryker and his strikeforce, the Purifiers, reform Bastion using his head and Nimrod’s body, offering him new life. The techno-organic being Mainspring also helps reconstitute Bastion post destruction.
Prime Directive: Destroy Mutants
Bastion confined Charles Xavier, AKA Professor X, in an OZT facility along with the artificially created mutant Mannites, and then captured young former X-Man Jubilee. Soon after, Bastion put OZT into full effect, utilizing Prime Sentinels—a new breed created from humans unknowingly implanted with nanotechnology—to attack the X-Men, quickly capturing several members. Bastion took control of the Xavier Institute and accessed Xavier’s files, despite opposition from Cable and Caliban of X-Force. The five captured X-Men and Jubilee ultimately managed to escape, and OZT was shut down by the United States government. Bastion was remanded into S.H.I.E.L.D. custody, but he escaped and returned to the former OZT facility. There, he absorbed the energy from the Master Mold unit with which he had created the Prime Sentinels and sought to transform Machine Man into the Sentinel Supreme; he was opposed by Cable, and seemingly destroyed.
Bastion survived and was recaptured by S.H.I.E.L.D. An attack by En Sabah Nur, AKA Apocalypse’s Horseman Death (actually a brainwashed James Howlett/Logan, AKA Wolverine), who was seeking to kill the Mannites, left only Bastion’s head still intact; Bastion survived.
Later, Bastion’s head was recovered by the robotic Gatekeeper servants of the techno-organic being Mainspring. Bastion co-opted one of the Gatekeeper’s bodies, and used it to attack the techno-organic hero Warlock and his allies. Defeated, Bastion’s head was recovered by Mainspring, who stripped away the layers of his programming to reveal the original Master Mold’s source code and, using the alien transmode virus he was infected with, rewrote Bastion’s programming, transforming him into Template. The virus soon took complete control of Template and forced him to construct a Babel Spire on Earth to signal the alien Technarchy. To oppose them, Mainspring destroyed himself along with Template, while Warlock managed to destroy the Babel Spire.
Bastion’s head was later retrieved by U.S. government agents in order to access the information he had stolen from Xavier’s files. The information was retrieved by the X-Men, but not before Bastion attempted to sow mistrust among them by confronting them with misleading holographic scenarios.
Bastion’s allies, the Purifiers, soon stole his body from a S.H.I.E.L.D. facility, adding it to Nimrod’s body once again. Back online, he sensed X-Force nearby and warned the Purifiers, allowing a quick getaway. He soon gathered several of the X-Men’s enemies, and resurrected a few, and used Magus, a techno-organic virus, to control them. He soon battled the X-Men and a coup within his ranks led by Matthew Risman. Overpowered, Bastion fled with the remaining resurrected enemies.
When the mutant Messiah, Hope Summers, arrived in the present timeline, Bastion rallied anti-mutant forces to kill her and her protector, Cable. He soon installed an impenetrable dome around the Bay Area, encompassing the X-Men’s island home of Utopia, destroyed their blackbird jets and incapacitated their teleporter. Bastion then opened a portal to Earth-811 and let loose mutant-adapting Sentinels upon the X-Men. The attack left the team with perilous injuries but they soon traveled to the future where they reprogrammed the signal driving Sentinels, allowing the X-Men to deliver defeat. Bastion attacked Hope himself, but Hope had already lost her foster father, Cable, in the fight and, enraged, destroyed the dome and Bastion.
But Bastion escaped death yet again by activating his temporal drives and fled to the future. Though he suffered catastrophic damage, and the time travel corrupted his systems. He landed at a time when mutants struggled against the tide of the Terrigen Mist, which killed many mutants. Feeling a loss of purpose, Bastion set out to save mutants from endangerment so that he could maintain his primary function of killing them. He met the original time-displaced X-Men and attempted to recruit them to his cause but they saw through his diabolical scheme. Bastion with his Sentinels decided a conflict with the teenaged team wasn’t worth it and teleported away.
He soon met with Claudine Renko, AKA Miss Sinister, Emma Frost, and Alex Summers, AKA Havok, under Utopia to aid them in their efforts to save Mutantkind. He destroyed his Sentinel Prime Units that were programmed to kill mutants, and helped his new allies spread the Mothervine virus, which would restore mutations from the mist’s destruction. He also directed Sentinels to usher in the new wave of mutants that were created from the virus. But Frost betrayed the group after learning that the newly created mutants would be under Miss Sinister’s control. She led an attack against Bastion and Havok with the support of a recently captured mutant force led by Lorna Dane, AKA Polaris. The mutant monk Shen Xorn, AKA Xorn, swallowed Bastion into a black hole, slaying him.
