Ferocious and terrifying, Dragotron (ドラゴトロン Doragotoron) is the Demon Emperor of the Predacons. Originally created by the mad scientist Shockwave, he and his Predacon brethren revolted against their Decepticon masters and scattered across the stars by the hundreds. Taking notice of a planet called Earth, Dragotron led a loyal band of Predacons on a mission to invade the planet, but they were defeated by a combined force of Autobots and Decepticons. Sealed deep underground by the power of a Legendisc, Dragotron now slumbers, awaiting the day that he may awaken and once again seize the power that is rightfully his.
At some point, Dragotron was sealed away by the blue Legendisc and was buried in Mount Fuji, where he remained till a stray rock thrown by a child led to a chain reaction that unearthed Dragotron's head. After seemingly awakening, he signaled his Four Oni servants, Bakudora, Budora, Gaidora, and Judora, to emerge from their sleep. The four subsequently set out in search for the other four Legendiscs.
Dragotron was soon recovered by the Predacons from the volcano, but was still unconscious. After finding out about the Legendiscs' time travel capabilities, Budora and Bakudora used the Legendisc within Dragotron to travel to Japan's past to find another Legendisc. Budora contemplated the idea of using the Legendisc to conquer history for himself, but discarded the thought when Gaidora questioned Budora's loyalties. However the pair was defeated by the Swordbot Samurai Team, who had also traveled through time to seek out the Legnedisc. Meanwhile, the other two Predacons Gaidora and Judora likewise used Dragotron's Legendisc to venture into the past in pursuit of another Legendisc, but the pair also failed, being defeated by the similarly time-displaced Swordbot Shinobi Team.
Later, Optimus Prime, the Commander of the Autobots, sensed that Dragotron's power was increasing, predicting that his eventual revival was immenent, and urged that the Swordbots acquire all the Legendiscs as soon as possible. However, Dragotron's power continued to grow to exponentially, to the point that his unconscious body began to glow with power and radiate bolts of energy, one of which happened to strike Gaidora, who was empowered by this sudden boost of energy and later wielded it in combat against the Samurai Team, absorbing the Jaki into his body to grow giant-sized, after having traveled once more into the past. However, his Swordbot opponents managed to eventually overwhelm and strike down Gaidora, reverting him back to his normal size and sending both him and Judora back to the present. Dragontron would further power up Budora and Judora before he fully awoke and suddenly burst out from underground, subsequently powering up to a red-based form and swearing to both defeat the Swordbots and conquer the world once and for all.
Dragotron proceeded to engage the Swordbots in battle, easily defeating them and resulting in Optimus Prime taking on a new form and joining the battle as Optimus Exprime. Despite the Autobot leader's help, Dragotron was still too much for the Autobots. Abducting the Autobots' friends Isami Tatewaki and Tobio Fūma, he took the boys to Mount Fuji where he absorbed both them and the four legendiscs they carried, gaining the power to cyberform the mountain and eventually the entire planet. Isami and Tobio managed to resist Dragotron, expelling themselves from his body, however he proceeded to absorb the power of the four Oni, making him invincible. Until, that is, it turned out that Tobio and Isami had duplicated the power of the Legendiscs in the hearts of justice, empowering Optimus to combine with Kenzan and Gekisoumaru. The Autobots' new combined form was powerful enough to take down Dragotron and use the Legendiscs to once again seal the Predacons away.