Bastion was "born" when the giant robotic Sentinel Master Mold, having absorbed the advanced Sentinel prototype Nimrod into its systems, fought the X-Men, who saw 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 were soon reawakened, and he began assembling the international anti-mutant strike force Operation: Zero Tolerance (OZT). They attempted to reconfigure the Sentinel force assembled by Project:Wideawake, but Bastion deemed most of them outdated. Instead, he had a number of humans secretly outfitted with nano-technology to be Prime Sentinels.
After Professor X voluntarily turned himself in after the events of Onslaught, Bastion confined him in an OZT facility along with the artificially-created mutant Mannites. Bastion also killed a Daily Bugle reporter who was going to report on Graydon Creed's history.
He then captured Jubilee. Soon after, Bastion put OZT into full effect, utilizing the Prime Sentinels quickly capturing several X-Men 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. OZT was shut down by the U.S. government after Henry Peter Gyrich and Senator Robert Kelly asked the President to intervene.
Bastion was remanded into SHIELD 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 SHIELD. Death (actually a brainwashed Wolverine) was sent to kill the Mannites, but also attacked Bastion, leaving only his head intact.
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 Shadowcat, Wolverine, and Gambit and a few other X-Men with them, but not before Bastion attempted to sow mistrust among them by confronting them with misleading holographic scenarios. Although they got the files, the X-Men was showing signs of doubt within themselves and their team.
After the events of the Messiah Complex, the Purifiers infiltrated a SHIELD facility with the help of some double agents inside and stole back Bastion's head and reattached it to Nimrod's body. Once online, he alerted the Purifiers on the presence of the X-Force in their church. After their escape, Bastion carried out a plan to finally eliminate the remaining mutant population by recruiting some of the prominent enemies of the X-Men and resurrecting others that have been dead and taking control of them by implanted them with the technorganic virus of Magus. After that, he face a coup 'd etat from Matthew Risman and his Choir, not knowing that the X-Force has followed Archangel, who sensed his metallic wings within the Choir. Bastion fought Wolverine, but calculated that the risk was too high to fight him directly and escaped with the resurrected X-Men enemies.
Powers and Abilities
Bastion possesses enhanced strength, speed, and endurance, flight via jet boots, command of other Sentinels, immunity to mutant attacks, laser vision and can shoot laser beam from his hands. It is also immune to psychic reading from telepaths.
Bastion also serves as the chief antagonist and final boss of the videogame X-Men Destiny.
Bastion appeared as both a villain and a boss in the videogame X-Men II: Rise of Apocalypse. He created the Perimeter Platforms, a facility with a series of advanced cannons and other weapons found on the coast of New York and used it to attack all escaping residents (both human and mutant alike) of war-torn New York during Apocalypse's invasion and new establisment of his prison camps in his obsessed search of the "Four who are One" (Sabretooth, Quicksilver, Emma Frost and Polaris), as well as to eliminate incoming Sentinels reprogammed and sent by Bolivar Trask to rescue all the New York refugees. He was defeated by both the X-Men and the Brotherhood of Evil Mutants and the Perimeter Platforms were inactive and possibly destroyed after the battle.