The Ash Plains were located at the very center of Dragon World, a forbidden zone no ordinary lifeform would ever want to visit.
The reason? Dragon World had ten times the Elemental Tide density than the Mortal Plane, but in the Ash Plains the density would randomly fluctuate between one and one thousand times, thus sinking this entire location into chaotic insanity.
It would drive one insane to use magic or fight there because nobody could know if the fireball they'd prepared would suddenly enlarge itself by ten times and explode them to death. Or perhaps one would spend great effort in preparing a Forbidden Spell that would mysteriously become nothing more than a tiny spark that sputtered out.