Magmatron commands the Predacon faction as the "Emperor of Destruction," succeeding the fallen Galvatron. He directs operations from his flagship, the Dinosaur, relentlessly pursuing Angolmois Energy capsules across the galaxy. His leadership blends charisma and ruthless pragmatism, often marked by frustration towards failing subordinates. Magmatron's primary adversary is Maximal commander Big Convoy; their rivalry involves mutual respect yet constant conflict, where Magmatron employs ambushes and hostage-taking to secure victory at any cost. Despite his villainous aims, he recognizes greater universal threats like Unicron, capable of temporary alliances with former enemies to preserve the cosmos he seeks to rule.

Magmatron possesses a unique "mitotic spark," enabling him to separate into three distinct dinosaur components: Landsaurus (a terrestrial Giganotosaurus), Seasaurus (an aquatic Elasmosaurus), and Skysaurus (an aerial Quetzalcoatlus). Each component moves and thinks independently yet remains part of his unified consciousness. They can merge into the unified beast mode Magmasaurus or combine into his humanoid robot form. In robot mode, he wields the Magma Blade sword and integrated missile launchers, utilizing his triple-changing capability for versatile combat on land, sea, and air.

In the *Beast Wars Neo* anime, Magmatron clashes repeatedly with Big Convoy and his Maximal recruits over Angolmois capsules. His forces skirmish across multiple planets, though his preference for commanding from the Dinosaur strains relations with field operatives like Guiledart and Saberback. The emergence of Unicron shifts his focus; after Unicron possesses Galvatron's corpse and commands the Blentrons, Magmatron redirects efforts to thwart the Chaos Bringer. Briefly trapped in a wormhole during this conflict, he later escapes to aid Optimus Prime and the Maximals defending Vector Sigma. Following Unicron's defeat, Magmatron allies with the Maximals to rebuild Cybertron.

The *Beast Wars II* and *Neo* manga offer an alternate origin: Magmatron and his Predacons were non-sentient dinosaurs transformed by Angolmois energy, permanently fusing Magmatron into the Magmasaurus form. His rivalry with Big Convoy culminates in a final battle against Unicron, where Magmatron suffers fatal wounds, reduced to a disembodied head. He bequeaths his Magma Blade to Big Convoy, requesting a warrior's death; Big Convoy later uses the sword to destroy Unicron.

In IDW Publishing's *Beast Wars* comics, arriving on prehistoric Earth, Magmatron attempts to convert stasis pods into a Predacon army. Maximal spy Razorbeast sabotages his plans, causing many protoforms to emerge as Maximals. After battling Grimlock and failing to capture Megatron, Magmatron is accidentally transported to temporal limbo. Observing Unicron's threat from there, he manipulates events to ensure Ravage allies with Maximals against Shokaract. Freed after Shokaract's destruction in the limbo, these events follow *Beast Wars Neo*, leading to Magmatron eventually serving on Cybertron's governing council.

Dreamwave Productions' unpublished *Beast Wars* comic would have depicted Magmatron as the overarching villain overseeing Megatron's trial. 3H Enterprises comics briefly feature him leading Dinobots on an Oracle-directed mission, where he sacrifices himself against the energy vampire "the Dweller," leaving only his sword behind. *Beast Machines* retcons Magmatron as a Maximal who, returning to a Vehicon-dominated Cybertron, joins the Dinobots under T-Wrecks. His triple-changing ability remains consistent, described as splitting into "Landsaur," "Seasaur," and "Skysaur" modes.