Megatron

Megatron is the leader of all Decepticons during the War For Cybertron. During the Attack on the Nemesis, Megatron was destroyed by a Leaper  and left floating in orbit of Cybertron. As it turns out, the Decepticon leader wasn't dead and went to Cybertron and found the Combaticons, who had been left behind. They remade Megatron into Galvatron and they took a Decepticon Dropship and arrived at Earth finding Starscream leading the Decepticons in Stealing Energon. Galvatron fought Starscream, but the cowardly seeker left with his wingmen and became rogue Decepticons. Galvatron took the leadership of the Decepticons again.

Personality
Megatron is ruthless and ambitious, and believes that peace can only come through tyranny. His original goal was to free Cybertron from the oppressive rule of the Autobots, but his lust for power eventually overrode that goal. He also does not tolerate people challenging his authority, and is known to swiftly dispatch those who betray him or defect to the Autobots.