Starscream (Transformers Armada)

Starscream is Megatron's younger third in command, and a recurring antagonist in the Unicron Trilogy. While somewhat anti-heroic in Armada, in the sequel series Energon and Cybertron he becomes a straight-up villain, serving as a secondary antagonist.

Armada
Starscream accompanied the Decepticons to Earth in the year 2010, but his relationship with his leader was a troubled one; where Starscream craved Megatron's respect, Megatron gave him not one ounce of it, consistently berating and even brutalizing him in some kind of twisted attempt to drive him to realize the Decepticon potential he could see within the younger 'bot. Granted control of the Star Saber but abandoned on the battlefield as part of a feint scheme, Starscream turned against his comrades and sided with the Autobots—not out of any desire to do good, but because he hoped they would help him destroy Megatron. Although he befriended the Autobots' young human allies—Alexis in particular—and appeared to slowly be coming around to their way of thinking, he fell victim to the manipulations of Thrust and Sideways, who tricked him into returning to the Decepticon fold. When the threat of Unicron appeared, however, Starscream could see that the only way forward was for Autobots and Decepticons to unite under Optimus Prime's leadership. Coming to a fatal decision, Starscream challenged Megatron to one last battle for respect, then attacked Unicron himself, sacrificing his life to convince his leader of the threat the chaos-bringer posed.

Energon
Ten years later, Starscream was resurrected by the alien Alpha Q using the power of Energon, sans his memories, with the intent that he destroy Optimus Prime and Megatron both. But Megatron was able to harness Unicron's power and even further mindwipe Starscream, transforming him—ironically—into his most loyal soldier in the war for Energon. When Megatron hurled himself into an Energon sun to entrap Unicron's spark, Starscream plunged into the star alongside his leader, and was believed dead.

Cybertron
In 2030, when the sun collapsed into a black hole, Starscream and Megatron were freed, and Starscream—his mind now his own once more—had a new ambition: to take leadership of the Decepticons for himself. He opted to bide his time at first, supervising the search for the Omega Lock on Earth while Megatron sought out the Cyber Planet Keys, but when he located an army of Ancient Decepticons, he made his big move. Taking on the entire Autobot army, Starscream stole the Omega Lock and the Cyber Planet Keys, and channeled from them the power of Primus, transforming himself into a skyscraper-sized giant. In a final battle with Megatron on the planet Gigantion, Starscream disappeared in a reality-sundering discharge of energy, apparently swept away across the dimensions.