Red Dragon spawns in Volcano inside Castle

The Red Dragon could spawn in the overworld. They can be found in ruined castles over a volcano. A volcano would be a simple mountain generation with a crater at it's peak, complete with a lava pool. Its peak could be decorated with sulfur, obsidian, basalt and other volcanic rocks. The castle would contain the red dragon in a underground chamber. It would guard the treasure inside. The dragon would have wings, but would not fly. It would use fire and knock back attacks. It could function as a precursor to the ender dragon. It could also be another place to find dragons breath.