Megatron (from transformers Energon)

Although he was believed dead by both the Autobots and Decepticons, Megatron, like Unicron, had survived the final battle. However, his body was a decayed husk absorbed into the equally damaged body of Unicron. Megatron lay dormant within Unicron for ten years until the being called Alpha Quintesson began his plan to re-energize Unicron. Seeing an opportunity, Megatron siphoned off some of the Energon that Alpha Q's Terrorcons stole, working towards his rebirth. To turn the Decepticons to his side, Alpha Q forged a sword from Megatron's spark, but when an enraged Scorponok stabbed Megatron's corpse with the blade, Megatron was fully revived. Taking the sword for his own, Megatron proceeded to take control of Unicron's body, sending Alpha Q fleeing in Unicron's head. Megatron thus restarted his campaign against Earth and the Autobots, seeking Energon to reactivate Unicron so he could use him as the ultimate weapon. Megatron eventually succeeded in bringing Unicron to the vicinity of Cybertron and transforming the planet-eater into robot mode. However, in an attempt to stop him, Alpha Q rammed Unicron's head, charged with the positive Energon of Earth, into Unicron's body. This triggered a reaction that caused a rupture in reality that led to a new region of space where Alpha Q recreated all the planets Unicron had consumed. Megatron immediately saw these new worlds as targets to acquire more Energon, and after another series of attacks, Megatron successfully amassed enough to fully reanimate Unicron. However, the chaos brings consciousness to invaded Megatron's body, taking over his mind.

Although Optimus Supreme was able to destroy Unicron's body, Unicron's mind lived on within Megatron, subtly directing him to attack Cybertron and uncover a reservoir of Super Energon beneath the planet's surface. Megatron immersed himself in the powerful liquid, causing him to assume a more powerful form, once again taking the name of Galvatron. Taking control of the planet, he forced the Autobots underground with Energon gas and used the planet's Energon Towers to relocate Cybertron to Alpha Q's region of space. Once there, Galvatron once again coated himself with Super Energon, causing growing to a colossal height. However, it was at that point that Unicron's influence seized control of his mind and directed him out into space to re-emerge with his spark. Optimus Prime went battle the Unicron-possessed Galvatron and, after Galvatron's hatred of Unicron caused his consciousness to surface again, Prime drained Unicron's influence from Galvatron and sealed it within himself. Enraged by Unicron's manipulations, Galvatron decided to destroy Unicron's spark but wound up being possessed by it once more. While struggling to fight the control of Unicron, Galvatron was confronted by Optimus Prime once again. Rather than fight him, Galvatron instead flew into the founding sun created by Primus, igniting the star and seemingly destroying himself rather than allowing Unicron victory.