C2423 Defy the Laws of Heaven
Only humans can reproduce beasts that defy the laws of nature, so after all these years of trying, he was still unable to hatch, so he decided to try it on the outside.
The meaning of the remnant soul was very clear. Regardless of success or failure, it could not return to the fairyland. She had to keep the secret of its origins, or else she would lose the right to enter the fairyland