Apparently he slew a forgotten Autobot leader known as Primon before he left Cybertron to form his empire. The Liege Maximo is rumored to be one of the original thirteen Transformers created by Primus, and is said to have spawned Megatron, along with the rest of the Decepticon race.
In Simon Furman's story Alignment, it was established that the Liege Maximo fell in a devastating battle with Grimlock and Megatron just as he was about to transcend normal reality and become a god in the same vein as Primus and Unicron.
|Megatron | Starscream | Galvatron|
|Marvel U.S./Marvel U.K.|
|Liege Maximo | Megatron | Shockwave | Straxus | Ratbat | Scorponok | Bludgeon | Jhiaxus | Galvatron | Cyclonus and Scourge | Soundwave|
|Megatron | Shockwave | Starscream|
|Megatron (Machine Wars) | Scourge (Robots in Disguise) | Megatron (Armada) | Scorponok (Energon)|