TIREK

Tirek is a centaur with a terrible talent – the ability to steal anyone's magic to make himself stronger. Ponies were left weak and virtually helpless. Many died, especially pegasi robbed of their flight magic and then plunged to their deaths. Tirek attempted to conquer Equestria by stealing the magic from every pony until he was more powerful than an alicorn. Mark Wells defeated him by tricking him into consuming a magic emetic, causing Tirek to literally vomit out all the stolen magic. The centaur was then condemned to Tartarus.

Despite his confinement, he managed to exchange letters with Cozy Glow, instructing her on ways to steal magic. Much later, he was freed by Grogar to fight on the goat's behalf along with several other villains. Ultimately, Tirek was defeated once more and sent back to his home dimension where his brother promised to keep him in check.

Sample art by and copyright to mmeloman.