The Megatron Military are a horde of Megatron clones created by Galvatron to overwhelm the Autobots. Each clone is gifted with a unique Fusion Cannon and they are capable of combining their blasts into a single devastating attack. No member of the Megatron Military is gifted with sentient intelligence, however, as they are all controlled by the will of Galvatron who was, in reality, the original Megatron before his upgrade by Unicron.
The Transformers manga
The Megatron Military appeared in the second issue of The Transformer manga series which took place during season 3 of the Generation One cartoon series (which, in Japan, took place in the year 2010 rather than 2006).
Rodimus Prime, Arcee, Kup, Blurr and Springer were at a monitoring station when their defense systems alerted them to the approach of a horde of Megatrons calling themselves the "Megatron Military". The Autobots engaged the Megatron clones in battle but were quickly defeated by their powerful Combined Fusion Cannon attack.
All hope seemed lost until Rodimus realized that the Megatron clones were being controlled by a single being. He managed to zero-in on Galvatron who was posing as a Megatron clone. Rodimus made short work of Galvatron, sending the angry Emperor of Destruction retreating into space. As soon as Galvatron lost control over the Megatron Military, the clones lost all their power and were easily disposed of.