Coredegon originated as a Mechtogan created by Fury but killed his creator upon gaining independence, declaring himself a being of free will. This mutation allowed survival without a Bakugan host and enabled transformation into a human disguise. He commanded three rogue Mechtogan—Slycerak, Exostriker, and Mandibor—and together they formed Mechtavius Destroyer, a powerful combined entity. Their initial plan targeted exterminating all Bakugan in New Vestroia to usher in Mechtogan dominance, but shifted to Earth after learning of the Bakugan's relocation. Arriving on Earth, Coredegon interrupted a battle between Dan Kuso and Gunz Lazar, dismissing Bakugan battling rules as trivial and attacking Bakugan in ball form to test their vulnerability. After initial resilience against Drago, Coredegon and his allies combined into Mechtavius Destroyer but were defeated by Dan and Drago's Dragonoid Destroyer. Facing dimensional banishment, Coredegon exploited Gunz Lazar's unconscious form and hatred toward the Brawlers to create "Wiseman," a human persona resembling Gunz. This disguise facilitated manipulation of the exiled Nonet Bakugan—including Betadron, Kodokor, and Mutabrid—by promising vengeance against Drago, descendant of their banisher. As Wiseman, Coredegon framed Gunz as a criminal, stole Battle Suits developed by Mira Fermin, and repeatedly battled the Brawlers. Though initially weakened, he gradually regained strength and shielding capabilities. After generating sufficient energy, he restored his allies' independence and abandoned the Wiseman persona, executing the Nonet Bakugan Balista for discovering Gunz. He offered the remaining Nonets a choice: return to the Doom Dimension or die. Combining into Mechtavius Destroyer again, he defeated the Brawlers but banished them to the Doom Dimension instead of killing them, seeking greater satisfaction in their despair. In the unaltered timeline, Coredegon destroyed Bakugan City, killing humans including Runo Misaki, Julie Makimoto, and Mira Fermin, then annihilated New Vestroia, killing Bakugan like Tigrerra and Preyas, with plans to target Neathia, Gundalia, and Vestal. His genocidal campaign was thwarted when the Brawlers and Gunz used the Current of Time to return to the past. In the final battle, Gunz and Reptak created Chromopod, enabling Dragonoid Destroyer to overpower and obliterate Mechtavius Destroyer, ending Coredegon's existence. Coredegon believed Mechtogan deserved universal supremacy and viewed Bakugan and humans as expendable obstacles. His cruelty included murdering allies like Balista and callously manipulating the Nonets. The character shared narrative similarities with figures like Sailor Moon's Death Phantom, including the "Wiseman" alias, manipulation of vengeful factions, genocidal goals, and defeat via time travel.