Diagnostic Drone

Decepticons
The cover of issue #3 shows that the original mini-series was in the same continuity as Marvel's superheroes. This was soon forgotten when the series became ongoing, but the shared universe between Transformers, G.I. Joe, and the superheroes was later relabelled Earth-91274 by Marvel Comics to separate it from the company's primary continuity.
Publication information
Publisher	Marvel Comics, IDW Publishing, Dreamwave Productions, Devil's Due Publishing, Fun Publications
First appearance	The Transformers #1 (September 1984)
In-story information
Base(s)	Homeworld: Kaon, Cybertron Other: Chaar, the Victory (G1), the Megastar (RID), Decepticon City (G1), the Nemesis (G1, ROTF, Animated, SG, Prime).
Member(s)	Leaders: Megatron/Galvatron (stated in exodus and the cartoon), Steeljaw, Liege Maximo, Unicron, The Fallen/Megatronus (in the movie series) Other: See: List of Decepticons

The Decepticons are the main antagonists in the fictional universes of the Transformers franchise and related comics and cartoons, and the enemies of the Autobots. The villains take many forms, and have many different origins and stories across the numerous different Transformers media, but in almost all incarnations, they are led by Megatron. They are typically represented by the purple facial insignia they all wear. Primarily, Decepticons have red eyes, while Autobots have blue eyes. They are usually known for their air power, especially since many of them turn into aircraft. They often turn into military vehicles, construction vehicles, expensive luxury or sports cars, and even smaller-than-human-sized objects.

In the Japanese version of the franchise, the Decepticons are called Destron or Deathtron (Japanese: デストロン Desutoron). The one exception to this naming convention is Car Robots, where the sub-group referred to as "Decepticons" in the Robots in Disguise adaptation, is known in Japan as the Combatrons (the Japanese name of the G1 subgroup known as the Combaticons). The overall name of the Robots in Disguise villain faction is Destronger. However, the Japanese Version of Transformers Animated uses Decepticon (ディセプティコン). As opposed to the Autobots' Supreme Commander or Prime, the Decepticons' highest ranking leader is often given the title Emperor of Destruction. Beginning with Animated, the Decepticon rallying cry has been "Transform and rise up!" in parody of the Autobots' "Transform and roll out!"

The Decepticons are from a race called Transformers - robots that can change into vehicles, mechanical devices and even animal forms. They waged war for eons on their home planet of Cybertron against the heroic Autobots. Both factions needed supplies, and select numbers from each side intended to get them. The Autobots weren't looking for a fight with the Decepticons, but they get one out in space anyway. When the Decepticons board the Autobots' ship it takes a beating and crashes onto Primitive Earth and knocks everyone unconscious. Millions of years later, in 1984 a volcano eruption causes a probe to give them all new forms which come from vehicles in the surrounding area. After the featured film The Transformers: The Movie, Megatron was reformed as Galvatron, and Optimus Prime was replaced for a time by Rodimus Prime, only to return later on.

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Wikipedia