C100 Thunder crystal spell

"Don't worry, it's not time yet. We've agreed on 49 days. We can't have too many and we can't have too few. Otherwise, the quality of the Thunder Crystal will be greatly reduced." He said this cautiously.

"This is really troublesome. Why don't you just tell me. What is the use of this Thunder Crystal?" This makes my heart ache to wait! " Li Mu said impatiently.

"Heh heh