We are special

Roy's eyebrows raised as he wondered whether it was as she said. Was the lava so hot that no one could go through it?

Casually inspecting the cervixes had helped him realize that they were doorways to the Spiritual Lava Sea.

This wasn't mentioned in the book. He found it on his own.

The truth is, because of reading the book, he knew some things about the summer land, but not a lot. His knowledge could only be said to be partially useful. However, he was coming up with the rest by using his information-gathering skill and connecting the dots.

Earlier, he had overlooked the content inside of the cervixes, but after being reminded by Delilah, he glanced at it scrutinizingly.

With one look, he found out everything there was to know about it.

It was ten times hotter than level-9 magic fire.

At some points, it was as hot as the sun.