The Fun of Bonfire Spire

About
First, you have to go through a lot of challenges to earn the Bonfire Gem. When you go to the boss battle with Cebollini, he has three modes.

Summary
After you defeat him, Noot transports you back to Bonfire Spire. Then, Slurpy gifts you with the Powerful Fire Relic, and the Bonfire Gem.

Tips
Using water may help, as water is powerful against fire.