another my version of King Sombra. This time I was sticking more to original design. This time I was thinking more about his story. My thoughts about him started to make sense, not like in the show "I AM A EVIL PONEH BLAH BLAHBLAH"
So.. it is impossible for unicorn to have so powerful magic..
first of all- his name is Amor, He's an unicorn, what understands love very well and ancient alicorns turned him into an alicorn of love - Prince Amor. (that explains his magic) His cutie mark was a black and purple heart with crown (THAT IS WHY his cape is covering his flank, he doesn't want to show his true self). He had his very special somepony - Crystal Pony Princess (maybe princess of truth), he loved her so much he could even sacrifice his life for her. One day he proposed her, but she rejected him. At that moment he lost a control and stabbed her just right in heart with his horn. (That explains the red part of his horn) Ancient alicorns took away his wings as punishment for what he have done, but powerful magic stayed. His name changed to Sombra and he turned into beast, a demon. Cape what he wore covers his cutie mark. He went to crystal empire and seeing every crystally coat made him go crazy, because that reminded him of Crystal Pony Princess, he enslaved crystal ponies (and their coats became normal pony like) and hid the Crystal Heart.
I hope this makes sense..
MLP FIM