Prior to the ascension of the Thirteen, the barbaric kingdom known as the Darklands sprawled over the western lands of Cybertron, ruled by the warrior-king Megatronus.

Fiction

2005 IDW continuity

Twelve million years ago, Megatronus was instructed in the ways of war by his mentor "Onyx Prime"—in reality, a convenient alias adopted by a temporally-displaced Shockwave. Knowing from the historical record that Megatronus' many conquests would set Cybertron and its inhabitants on the path to unification, he turned his pupil loose on the lands to the west, and Megatronus' early campaigns led to the expansion of the Darklands. The First Who Was Named

Megatronus' growing ambitions soon led him and his army of Darklanders to invade neighboring territories, conquering the Forgotten Plains and sacking Septimus Prime's city of Protohex. The gladiator slaves Galvatron and Arcee were among those from Protohex who joined Megatronus' forces, Origin Myths and thus would identify the Darklands as their home. The Mind Bomb The Crucible Future Glories Lost