Mechtavius Destroyer emerges as the primary antagonist in Bakugan: Mechtanium Surge's second arc. This formidable entity is a composite Mechtogan Destroyer, born from the fusion of four rogue Mechtogan hailing from the Doom Dimension: Coredegon (the leader), Slycerak, Exostriker, and Mandibor. United, they pursued the eradication of all living Bakugan to establish Mechtogan supremacy. Each component contributes unique combat abilities. Mandibor features a spring-loaded chest firing lasers, deployable shoulder blades, and forearm blades for close combat. Exostriker wields a concealed dual blaster cannon within its skeletal frame and spiked shoulder blades. Slycerak utilizes agile movements, forearm blades, a poisonous stinger tail, and dual spinning saw blades ejected from its chest. Coredegon functions as the central unifying force. Mechtavius Destroyer first manifested in Bakugan City shortly after humans and Bakugan achieved peace. Its debut battle against Dragonoid Destroyer resulted in defeat. Subsequent summonings, orchestrated by Wiseman and the Nonet Bakugan, led to repeated confrontations with the Battle Brawlers and their allies. Key engagements include a battle against Drago, Jaakor, and Radizen, where Dragonoid Destroyer and Radizen's Battle Suit: Blasterate secured victory, and a larger conflict against multiple Bakugan including Drago, Jaakor, Radizen, Roxtor, Reptak, Orbeum, Skytruss, Magmafury, and Betakor, again defeated with Battle Suit assistance. Throughout the arc, Mechtavius Destroyer displayed escalating power and destructiveness. It banished defeated Battle Brawlers and their Bakugan to the Doom Dimension. Later, it killed and absorbed multiple Nonet Bakugan (excluding Betadron), significantly increasing its size. This enhanced form devastated Bakugan City and traveled to New Vestroia, eliminating Bakugan such as Storm Skyress and Alpha Hydranoid—though these events were later undone via time travel. The final confrontation spanned multiple dimensions. After battling Gunz Lazar and the surviving Nonets, Mechtavius Destroyer engaged Dragonoid Destroyer in a decisive one-on-one conflict. It was ultimately obliterated in this battle, erasing its existence from the timeline and preventing its future actions.