Speak to Master Li Fei in the Shrine of Inner-Light.
You've done very well this far, my student. You have the materials you need to rekindle Huo, the spirit of fire.
In the cave to the southwest he awaits, but he is guarded by Master Li Fei, the pandaren elder you met in the Cave of Meditation. Go to Master Li Fei with the offerings. Prove yourself, then meet with Huo.