Mephiles, Silver the Hedgehog and Blaze the Cat, Sonic Boom theme.

Despite the problems and hatred STH 06 got (namely Elise and her Romance with Sonic and the LOADING screen) the game actually had a decent dark tone story line and a really cool villain: an actual menace manage to kill Sonic in a somewhat graphic way for the franchise. It was unfortunate that the game was brought out with the problems it did.

I would change however the premise from Elise to Silver: he should have been Mephiles victim to release the Flames of Disaster. When you think about it, if he achieve the Apocalypse in the Future, why the need to train Silver, and have somewhat like Blaze close by and let him meet Sonic. Even going to the past was a bad move ended up robbing him from his goal HIMSELF.

I might revisit these guys again soon.
My envision shows Mephiles as an old hermit wizard, which is dying from his separation with Iblis; as proven by the bandages and lack of a leg, retaining his powers, but unable to fix himself, he trains Silver for years so he (unbeknownst to him) can become the Host for Iblis.