The Thunder Palace had Lord Thunder Emperor as its head. Below him were the four great Thunder Kings, nicknamed North South East and West. Zuo Fei was one of the Thunder Kings named the Eastern Thunder King.
The Lord Thunder Emperor had obtained the Thunderbolt Ancestral Symbol. However, because of that, their Thunder Palace was targeted by those Yimos, which launched a large scale invasion. They send a king grade and two general grade Yimos. The Yimos waited until the Lord Thunder Emperor was attempting the reincarnation tribulation to break into the Reincarnation Stage before attacking.
Is a space carved out by Lord Thunder Emperor himself. Other than him, no one else can enter. The Thunder World also requires a key to enter. The Silver Towers. One needs to assemble all three of them in order to open the Thunder World.