C105 Rain clearing!

After Jiang Feng entered the imperial city, he had been cultivating in seclusion. How did he know that the Thunder King was refining the heart of thunder?

What other lightning source was there? What was this?

Only Yu Tong, with her clear eyes, had a strange look on her face. Her father had told her before that the Thunder King refined the heart of thunder, but it was not the source of lightning