Old tales retold, this is a world based on DND.
The rulebooks Leon had read before could only be used as a reference.
Speaking of rulebooks, there are many versions, among which the most famous are the third and fifth editions.
In the third edition rulebook, the Elder Brain's challenge rating is as high as 25, equivalent to that of an Ancient Red Dragon, and only slightly lower than the Githyanki's Lich Queen Vilakis… What's puzzling is that despite being so strong, the Elder Brain chooses to cautiously hide in the Dark Territory, fearing enemies will seek it out.
Meanwhile, in the fifth edition rulebook, the Elder Brain's power has been drastically nerfed, with a challenge rating of only 14… Well, "only" might be unfair; after all, even mature Red Dragons are at that level.
