In this chapter, we learn that the demon king and his men have selected a very high-level spirit stone, a "mid-level rainbow spirit stone" . In other words, they've opened the stone up to a higher level than it was originally supposed to be. This means that the price of the stone has gone up by a factor of ten. The demon king tells his men to pack up the stones and bring them back to him.
In this chapter, we learn that the demon king and his men have selected a very high-level spirit stone, a "mid-level rainbow spirit stone" . In other words, they've opened the stone up to a higher level than it was originally supposed to be. This means that the price of the stone has gone up by a factor of ten. The demon king tells his men to pack up the stones and bring them back to him.