Who is Mephiles the Dark?

Mephiles is a demon from another realm (Sonic 06 displays Mephiles) that was formed from Shadow's shadow. He was sealed in the Diamond. But before that, he wanted to rule the world and to merge with the Iblis Trigger (Sonic. Play 06 to see more) but is now sealed in the Crystal. He has crystals on his body because he was sealed in it for so long. http://media.moddb.com/images/members/1/277/276820/mephiles_rules.jpg