Thunderwing (MLPTP: FIM)

Thunderwing is the evil alter ego of Thunder Streak and the main antagonist of My Little Pony Transformers Prime: Friendship is Magic

Bio
Thunderwing was created when Thunder Streak's bitterness got the better of him. He planned on shrouding Equestria in eternal night and plunge it into chaos at the same time. However, his plan was foiled when Luna and Celestia used the Elements of Harmony to banish him to the moon forever.

My Little Pony Transformers Prime: Friendship is Magic
Thunderwing's escape was prophesied to happen a thousand years after his banishment in a book Optimus and Twilight were reading. He later made his escape that night at the Summer Sun Celebration and announced his plan to make Luna's night last forever and plunge Equestria into chaos. He then took out a few guards before leaving. He then tried to stop the Autobots and ponies from finding the Elements of Harmony so they could use them to defeat him but his attempts were foiled by their acts of friendship. He then took the Elements so they could not be used but Optimus and Twilight were able to follow him and tried to use the Elements to stop him but they don't work and Thunderwing smashes the Elements, explaining that they were foolish to think they could stop him and that they would never Celestia or Luna or the sun again and that Luna's night would last forever and that all of Equestria would plunge into chaos. But Optimus and Twilight tell him that if he thinks he can destroy the Elements just by smashing them, he's wrong because the spirits of the Elements of Harmony are standing right in front of him. The spirit of honesty is represented by Applejack and Bulkhead, the spirit of kindness is represesnted by Fluttershy and Ratchet, the spirit of laughter is represented by Pinkie Pie and Smokescreen, the spirit of generosity is represented by Rarity and Bumblebee, and the spirit of loyalty is represented by Rainbow Dash and Arcee. Thunderwing tells them they still don't have the sixth Element and that the spark that was supposed to ignite their magic didn't work. But Twilight tells him that it did but it was a different kind of spark and that spark ignited inside her and Optimus was what they needed: the Element of Magic. The Element of Magic appears in an orb above Twilight and Optimus and they tell Thunderwing that when the Elements are combined, they create the sixth Element, the Element of Magic. The Element of Magic forms into a crown and they fire a rainbow beam which overpowers Thunderwing and engulfs him in a rainbow tornado and reverts him back to Thunder Streak. The Princesses are freed from their prison and reunite with Thunder Streak.

My Little Pony Transformers Prime: Luna Eclispsed
Thunderwing appears as a statue and then in real life when Thunder Streak becomes him to scare the fillies and colts on Nightmare Night.

My Little Pony Transformers Prime: Do Princes Dream of Magic Sheep
In one of Thunder Streak's dreams,

My Little Pony Transformers Prime: The Cutie Re-Mark
When Twilight, Ryan, Spike and Optimus

Appearances

 * My Little Pony Transformers Prime: Friendship is Magic
 * My Little Pony Transformers Prime: Luna Eclisped
 * My Little Pony Transformers Prime: Princess Twilight Sparkle (flashback)
 * My Little Pony Transformers Prime: Do Princes Dream of Magic Sheep
 * My Little Pony Transformers Prime: The Cutie Re-Mark