King Sombra rules his kingdom, the Crystal Empire, with an iron hoof. This malevolent unicorn's heart is supposed to be "black as night". He has an imposing demeanor for a unicorn. He has a gray coat, red eyes with dragon-shaped slits, a flowing black mane and tail, a red curving horn, and sharp teeth. His outfit consists of metal armor, a crimson royal mantle, and a grey headpiece with two curved spikes on each side, a little cylinder in front between two red spikes, and three black sections that cover his snout and sides of his face.

Like all unicorns, King Sombra could use magic for a variety of purposes. However, he possesses a multitude of dark magic-based talents. At some points, his sclera become green with purple smoke coming out, and when forcing anypony to see their worst fears, his eyes turn completely green with the pupils disappearing for a moment.

Sombra sits on his throne chair in the Crystal Empire's castle, eating some grapes from one of his enslaved Crystal Ponies. Thank you, now leave my sight. Sombra said with a demanding voice. As the Crystal Pony left, Sombra suddenly heard a stranger walk inside the castle's throne room. What the-!? Who dares enter my kingdom unannounced!? Reveal yourself at once! Sombra shouted at the new stranger.