Following the Autobot City Massacre, several Decepticons were critically injured, and deemed expendable when Astrotrain requested that his Decepticon passengers jettison some weight. All the wounded Decepticons, even their commander Megatron were cast adrift in space, only to be recovered by the monster planet, Unicron. Unicron made a deal with Megatron - if Megatron destroyed the Autobot Matrix of Leadership, Unicron would give him a new body and new troops to command. Megatron reluctantly agreed, and was transformed into Galvatron. The other Decepticons with him became Scourge and the Sweeps, and Cyclonus, and his armada. These warriors were served Galvatron loyally, until the final battle with Unicron, when Rodimus Prime hurled Galvatron into the void of space, to parts unknown.
CYCLONUS (AND THE ARMADA)
Cyclonus was formerly the Decepticon jet warrior, Skywarp. The armada was a single clone of Cyclonus, formerly the Insecticon, Bombshell. Both Cyclonus units were apparently identical, with the same personality, or lack therof. However, following the events of 2005, only one Cyclonus unit remained active. Any instances where multiple Cyclonus units were seen was erronious. It is presumed that the second Cyclonus was destroyed during the final battle with Unicron. The remaining Cyclonus was blindly loyal to Galvatron, and made it his first priority after the relocation of Decepticons to the sterile planet of Charr to find Galvatron. He, Scourge, and the Sweeps used Unicron's databanks to locate Galvatron on the planet Thrull. Despite the fact that the pools pf plasma lava on the planet had damaged Galvatron's mind and vocal circuits, and left him dangerously insane, Cyclonus remained loyal to him.
Cyclonus transforms into a spacecraft, capable of increasing his mass to the point that he is big enough for Galvatron to pilot. He has a cunning mind, and is particularly intelligent and scheming. In fact, if he was not so loyal to Galvatron, he would be more than capable of overthrowing him and leading the Decepticons himself.
When Cyclonus was infected with the Hate Plague, he DID overthrow Galvatron, and battled him very effectively. Galvatron also eventually succumbed to the plague, but the reborn Optimus Prime used the wisdom of the Matrix to cure the madness of the plague and save all those who had been infected. Months later, when the Decepticon stole the key to the Plasma Energy Chamber, Cyclonus was among the Decepticons who pursued the small group of Autobots who had stolen the key back from them to the planet Nebulos. There, Cyclonus was forced to bond with a Nebulan known as Nightstick, converting his weapon into an exo-suit for the Nebulan, and becoming the first Decepticon Targetmaster. The power of Cyclonus's weapon was increased ten times by this process. Cyclonus was unable to prevent the Autobots from restoring Cybertron's Golden Age, and was blown across the galazy inside Scorponok along with the other Decepticons, by the backlash from the Plasma Energy Chamber. He has not been seen or heard from since.
SCOURGE (AND THE SWEEPS)
Scourge was formerly the Decepticon jet warrior, Thundercracker. The Sweeps were two clones of Scourge, formerly the Insecticons Kickback and Shrapnel. While Unicron was only seen to create these two Sweeps, mere seconds later, there were four Sweeps flying behind Scourge. Over the following year, numerous Sweeps were terminated in a variety of ways, but there always seemed to be more coming from somewhere. Generally, on missions, three Sweeps were seen to be with Scourge. During a battle on Earth's moon, two Sweeps identified themselves as "Sweeps 6 and 7", indicating that many more than the original two existed (Ref: "Call of the Primitives"). There are four possible explanations one could give to verify the existence of so many Sweeps; 1) All accounts of Sweeps in excess of two are erronious (which seems extremely unlikely); 2) More Sweeps were simply built (but then, they would need to be taken to Vector Sigma on Cyberton to be programmed, and that was impossible, as the Autobots controlled Cybertron, and in any case, the Key to Vector Sigma had been destroyed); 3) Unicron made more Sweeps, off-screen (possibly from the Reflector robots, but even then,this would only bring the total to five); and 4), my personal favourite - after being converted into Sweeps, Kickback and Shrapnel retained the Insecticon ability to create clones of themselves, thusly providing a never-ending supply of Sweeps. However, we will never know the truth.Scourge and the Sweeps transform into spacecraft, equipped with rear-mounted laser blasters, which, when concentrated, are capable to blowing a Transformer to smithereens (Ref: Ultra Magnus in Transformers: The Movie). Scourge was generally loyal to Galvatron, but more through fear of him than anything else. He is an expert tracker, and the Sweeps act as his huntsmen.On one occasion, Scourge gained the power of the Autobot Matrix of Leadership, when Rodimus Prime actually managed to lose it, and led an attack on Autobot City. After a battle, Hot Rod reclaimed the Matrix, and Scourge was reprimanded by Galvatron. Several months later, after the Hate lague scenario, the Decepticons attacked Autobot City in force, and stole the key to the Plasma Energy Chamber on Cybertron. Scourge activated the chamber using the key, but was instantly knocked off-lin by the plasma energy. A small group of Autobots reclaimed the key, but the energy overloaded their ship's engines, and sent then careening through space, to wind up crashing on a small planet called Nebulon. Scourge was among the group of Decepticons who followed them there. On Nebulon, he was forced to bond with a Nebluan called Fracas, transforming his weapon into an exo-suit for the fleshling, becoming a Decepticon Targetmaster. Scourge's weapon became ten times more powerful through this process, but he was unable to stop the restoration of Cybertron's Golden Age, and was blown across the galaxy inside Scorponok along with the other Decepticons by the energy from the chamber. Neither he, nor Fracas, nor any of the Decepticons have been heard from since.