Magmatron is one of the only a few known reverse-combiners (the others being Sky Lynx and the Duocons in the original series, and Tidal Wave in Transformers: Armada series) Three beasts, a Giganotosaurus, Elasmosaurus and a Quetzalcoatlus, can combine into a humanoid robot form, or that of a giant Fuzor with attributes of all three beasts. While in his beast modes he is able to maintain a singular consciousness/personality. Sometimes he is referred to as a Triocon, a being with technological relations to the Decepticon Duocons, with three split forms (relating to land, sea & air, respectively) instead of two.
Magmatron's tech specs paint him as a study in contradictions. On the one hand, he is violently impulsive and tends to charge into battle without thinking. On the other, he is known to rationally and coolly appraise situations before committing himself fully. He is the successor to Galvatron (the Beast Wars II version, not the original) as Predacon Emperor of Destruction. Despite the inherently treacherous nature of his Predacon underlings, Magmatron's charisma is so powerful that many times they submit to his authority without question.
Hasbro released Magmatron as part of the Beast Machines toyline. The Magmatron toy was part of the Dinobots faction of Beast Machines which featured no new molds but did release molds previously unseen in America. Unlike all the others however, Magmatron was neither repainted nor renamed and his bio even suggested that he may be the same Magmatron of Beast Wars Neo.
Magmatron is described as a fierce warrior determined to succeed at all costs, much like his original. However, his new tech spec gave him a new background mixed with his old: He was returning from a mission to acquire energy capsules (a reference to the Angolmois energy capsules of Beast Wars Neo) to discover Cybertron overrun with armies of mindless Vehicon drones. This bio identified his title of “Emperor of Destruction” (which is not an actually rank in most mainstream Transformer fiction) as moniker given to him as a testament to his destructive presence on the battlefield. Magmatron’s ability to separate into three distinct bodies (identified as: Landsaur, Seasaur, Skysaur respectively) is attributed to a “Mitotic” spark.
Although the Dinobots' intro states that the Dinobots received their beast modes through the slicing of Dinobot's DNA, it is likely that the Oracle also used the fossil chamber (seen in the Beast Machines TV Series) to utilize Giganotosaurus, Elasmosaurus and Quetzalcoatlus DNA.
Magmatron does not appear to be a homage to any of the original Dinobots team in name or form. He appears instead to be a direct homage to himself from Beast Wars Neo.
As Unicron took Galvatron's corpse as a new body, Magmatron realised the disaster he had unleashed and his forces challenged Unicron. They were defeated, and Magmatron was left trapped in a wormhole. Eventually escaping he teamed up with his rival Big Convoy to stop the Unicron possessed Vector Sigma. After Unicron's defeat the two worked together to rebuild Cybertron.
Realising that time was running short, Magmatron also recovered the remains of Ravage and used a blank protoform to bring him back in a stronger Transmetal II form, intending for him to stay behind and hunt down Razorbeast. Magmatron now realised the only way to divert the Council's suspicion was to acconplish his assigned goal - capturing Megatron. Revealing himself to Megatron, the two would-be tyrants battled, but after Megatron gained the upper hand he was captured when Magmatron's lackeys managed to put a restraining collar on Megatron. Magmatron aimed to send him back to Cybertron, but was interrupted by an unexpected foe - Grimlock. As the two battled, Razorbeast and Optimus Minor sabotaged Magmatron's transport machine. Magmatron eventually defeated the former Dinobot, but Razorbeast used Magmatron's own chrono-wristband to battle Magmatron and stay ahead of his blows, before Minor used his own time displacement band to send him back to Cybertron empty handed.
The follow-up series, The Ascending, revealed Magmatron's fate. The failed time-jump had consigned Magatron to a temporal limbo, able to see the whole of time and space, but affect nothing. When he saw the Cybertron of the future being destroyed by Unicron and Shokaract, Magmatron used what power he had to ensure a signal from prehistoric Earth summoned Lio Convoy and the Pack. Then, when Ravage tried to use the time displacement band for his own ends, Magmatron was able to communicate with him and instruct him to call a truce with the Maximals against the Chaos-Bringer.
During the battle on Cybertron the Maximal Snarl was able to shunt Shokaract into limbo with Magmatron, where the truth of Unicron's plans were revealed. Shokaract destroyed himself and Magmatron was freed, returning to Cybertron.
Notably, IDW's Beast Wars: Sourcebook profile on Magmatron places the events seen in Beast Wars Neo before those of The Gathering, establishing that after he had tried to follow up Galvatron's intentions to gather Angolmois in Neo he and Big Convoy both ended up on the bi-partate committee for state affairs, setting up the events of the comic.
The sketch gallery in the Beast Wars; The Gathering trade paperback indicates that Magmatron had his "split" Tricon technology before he received his beast modes. His Cybertronian modes were a tentacled submarine, a hovercraft and a tank.
Although the Dinobots' box text states that the Dinobots received their beast modes through the slicing of Dinobot's DNA, it is likely that the Oracle also used the fossil chamber (seen in the Beast Machine TV Series) to utilize Giganotosaurus, Elasmosaurus and Quetzalcoatlus DNA. He was interpreted incorrectly as the factions’ leader, as opposed to the T-Wrecks, the Dinobot Commander, probably because he outranked T-Wrecks on the Tech Specs, even though, as seen in the comic scene right, T-Wrecks is treated as the leader.
In Departure the Wreckers, Mutants and Dinobots arrive on Cybertron and are sent on missions by the Oracle. Arcee, Dillo, Mol, Rav, Skywarp, Cyclonus, Rotorbolt and Devcon join the Wreckers. In Betrayal the Dinobots are attacked by the Dweller.
When shown later, the Dinobots were missing several members, including Magmatron. It is presumed that the missing members were victims of the Dweller, but since the Dweller doesn't kill its victims, only turns them into energon-zombies, Magmatron may not be dead.