Sonic the Hedgehog (2006)/Flame Core

A possible homage to Red Mountain from Sonic Adventure, Pumpkin Hill and the Dark Chao Garden from Sonic Adventure 2, Black Comet from Shadow The Hedgehog and Lava Reef from Sonic & Knuckles. This level features a volcano and it's surrounding mountains. All the characters start outside the Volcano and finish the level inside it. At the end of the stage, the character winds up meeting (either by accident or by intent) Iblis.
 * Sonic's Story (5th Stage): Teamed up with Shadow and Rouge, Sonic and the others search for a Chaos Emerald here to get back to the present, but end up confronting one of Iblis' forms instead.
 * Boss: Iblis Phase 2
 * Shadow's Story (4th Stage): Also stuck in the future, Shadow and Rouge assist Sonic and the others in their search of a Chaos Emerald here to get back to the present.
 * Boss: Iblis Phase 2
 * Silver's Story (Final Stage): After returning to the future with knowledge of how to seal Iblis, Silver rushes off to fight with him, but doing so requires a high price to pay.
 * Boss: Iblis Phase 3