Lord Tirek the Supreme (spoilers)

In case anyone is wondering about his appearance - specifically the wings, and its 'similarity' to an in-show demon form we've seen in Equestria Girls, then that's because it is. With the aid of Professor N. Shroud, along with his Order of Midnight Masters, he pulls a F.O.W.L. during the big fight with "The League of Villains" or at during that story arc specifically, and goes throughout Equestria, and other places the Mane Six have gone to - even into the Power Ponies universe, courtesy of the good professor's extra-dimensional tech which he'd actually spent years developing. And it worked perfectly for Tirek's purposes: stealing every known magical artifact in the universe of "Friendship is Magic".

Even cheating by going back in time to a point where some items would be destroyed, and have them switched out with fakes in order to ensure noone suspects a thing.

But once his allies have attacked every known region of the world, and those connected to it, their power now only has risen beyond what Tirek and Apophis' pawns had accomplished. He even recovered Grogar's Bell the moment he presented himself in his new form via mystic hologram before the Sisters and Discord could turn them to stone: even rescuing the only two in their number of value to him, in the form of King Sombra and Erebus, The Pony of Shadows, while his own centaurian clone, and Grogar's secret double were revealed as LMRs - an acronym for Life Model Replicas, which can be used as PERFECT copies of whoever imprints themselves in some way onto them. The two melted into wax, and Tirek revealed his dark machinations. Even the princesses and Discord could sense what was going on, even as Tirek himself showed the little army the mass theft he had pulled while they were all distracted - which even gave time to even snatch Neighsay's EEA Medallion, as it was another on his list. Either way, despite The Mane Six's protests, Lord Tirek assured them that things were only going to get worse from here on.

For the true War for Light and Darkness has begun.

And thanks to N. Shroud enhancing the human Twilight's magic siphoning spectrometer, followed by the mad doctor doing as she did and draining Sunset Shimmer, and the Humane Six of both their magic, and once more the magic of the Canterlot High portal: thus producing mastery over the aspect of space, itself. The raid on Canterlot castle gave Tirek the ample time to recover the Fists of Might, and Ability, and finally complete the triage of Chronos. And as he had instructed decades ago when he communed with Professor Shroud thanks to Starswirl's time travel scroll, and the Eye of Destiny, N. Shroud presented the stolen magic to his master, and handed the techno-locket he had personally rebuilt and improved to double the magical output. With the Gems of Chronos, and The Rainbow of Darkness combined, such an influx of power brought forth what many might actually consider the true, final evolution of Tirek's cycle of power. And now, he would be rid of the similarity he saw in himself match his damned father, which tormented him since Scorpan's return. But now he would be free of all those physical aspects, and shed away the final scraps of his flawed self. His features becoming more human as his equine body faded away til only a pair of hybrid human-equine legs remained. His beard, and muzzle and white hair ceased to exist as the black fur on his body pulled into him, and seemed to leak into a new extension of ebon black hair. What's more was he had all of the important aspects of his old body, such as his powers, his physical strength, and both demonic horns and eerie eyes of shimmering yellow. Now, though, he had a pair of demonic wings, and a slender, but nimble, and prehensile tail behind him. One that would be donned in a newly enhanced version of his Dark Armor, which had now become less like a mere suit, and more like a physical extension of himself - a part of his own body. He was faster, stronger, smarter and younger in body and soul, twice as alive, and ten times more wicked. He was in his prime, and more than ready to remind this world of why it once feared the Darkness of Midnight.

For now, this would be the time The Devil gets his dues.