Flame Core

Description
Flame Core is a volcanic level in Sonic the Hedgehog. It is just like Crisis City, approximately 200 years in the future. In Sonic and Shadow's stories it is overpowered by a Chaos Emerald. In everyone's stories Flame Core is inhabited by Iblis type monsters and Iblis is a boss to face afterwards.

Sonic
In Sonic's story, he goes to Flame Core to escape Crisis City and retrieve a Chaos Emerald. He starts off outsite the volcano then inside it. Sonic then fights Iblis Phase 2. After that he does a "Cross-Chaos Control" with Shadow to escape to the present.

Shadow
In Shadow's story, he goes to Flame Core to escape Crisis City and find a Chaos Emerald. His version of the stage is slightly harder than Sonic's. He starts off outside the volcano, then goes inside. Shadow fights Iblis and Mephiles monsters. Afterwards he fights Iblis Phase 2. Then he "Cross-Chaos Controls" with Sonic, but then decides to fight Mephiles (Phase 1). [{Shadow]] gets back to the present because Mephiles teleports him back.

Silver
In Silver's story, he goes to Flame Core by using "Cross-Chaos Control" with Sonic and goes there. He starts off inside the volcano. Silver fights Mephiles and Mephiles monsters. At the end of the stage he destroyes a giant ball of flame, which is part of Iblis. After wards he goes on outside and defeats Iblis Phase 3.