Five years ago...
Three of Equestria's greatest enemies formed an alliance and conquered it. They combined their magic to alter the senses and memories of the princesses and the lands inhabitants into believing they are royalty and their army come to join them. Before they could act, Princess Luna sent an ancient artifact to a friend of the main 6 to train for the coming battle.
Five years later...
Echo Wave has trained himself to defeat the monsters, their creators and free his home from their evil. Even if his friends and his land view him as evil and try to stop him, he will continue his mission. He shall be the hero that strikes from the shadows. He shall be known as Kamen Rider Shade.
(Kamen rider franchise belongs to it's rightful creators)
(Ponies are Anthro)