The oval-shaped black egg lay quietly in the palm of his hand, about the size of a chicken egg.

This was the so-called [Primal Demon Egg].

"It also absorbs demon crystal cores to hatch, just like the [Abyssal Key]... However, the [Abyssal Key] has a higher priority for charging. Once it's charged, I'll see if there are any extra demon crystal cores for you."

With this thought, Su Yuan put it away.