Chapter 674: Chapter 667: Conjecture Confirmed

After hearing Zhuyan Yu's explanation, Tangmo suddenly exclaimed in enlightenment: "Ah, no wonder. Previously when I replenished her with magic power, I noticed she could at least withstand the magic power injection of three magic crystals."

"Three magic crystals, how concentrated?" Nightingale asked, frowning.

"They are number nine," Tangmo replied.

"Number nine, that's quite concentrated," Nightingale mused, lowering her head.

Magic Crystals can be divided into ten levels based on their concentration, which are marked by numbers. Industrial-grade Magic Crystals should be at least level five and above, while those used for military purposes need to be at least level seven and above.