Out of a series of drawings that Delta and I collaborated on where we thought up how the old villains from MLP would be remade in Friendship is Magic. (Granted, some of them are radically different from their source material).

This one is Tirek, the wielder of the Rainbow of Darkness.
I know that Tirek was established in the latest episode of Friendship is Magic, but this was drawn long before that episode was even alluded to.