C113 Terrifying Soul Power.

If they wanted the Formation Demonic Key to return to normal, they had to inject their soul energy into Guu Feng's demonic bone.

The soul energy required by Guu Feng's demonic bone was just too great.

Even though Gu Yue had almost used up 90% of her demonic soul, she was still unable to awaken the Formation Demonic Key.

Gu Yue's demonic soul was on the brink of exhaustion