Malcontent

Though the appointment of Optimus and Megatron as co-leaders of Cybertron heralds a new era for the planet, one without conflict, not every Cybertronian agrees with the new political and societal system. Those who oppose the order are appropriately named the Malcontents. As head of the Defense Force, it is Megatron's task to make sure they do not pose a danger to the population, a task he readily latches onto. Because whatever actual menace the Malcontents are, having Cybertron need him to protect it against an identified enemy is a gateway to absolute power.

Fiction

IDW Dark of the Moon comics

Four Malcontents had agreed to meet at Tyger Pax, information that made its way to Soundwave and from him to the rest of the Defense Force. Megatron personally led a unit to capture or, preferably, kill them. As by Megatron's wishes, the soldiers sharing his views made sure not one of the Malcontents survived, despite that none of them put up any resistance and instead begged to be spared.

Later that day, Megatron called Optimus to his citadel to inform him of the increasing threat the Malcontents posed. Megatron demanded to be temporarily made sole leader of Cybertron in order to deal with them efficiently. Optimus accepted this change in hierarchy, though with hesitation. Foundation #2 He should've acted on his doubt, because Megatron eventually used his power to create his own faction, the Decepticons, and declared war on everyone who was not part of that faction. Among the first he had attacked were the members of the Science Division at excavation site LT34. Unaware of Megatron's declaration of war last night, the poor saps thought the assault was organized by the Malcontents until a rescue unit arrived and explained the survivors who was their true enemy. Foundation #3