Did the Crystalians teach Azur & Luzat? Did the masters of glinstone teach the Crystalians? Or was it something else entirely?
Crystalian sorceries mimic the most powerful glinstone spells
Reflections of The Ancient Plot in the Night of Black Knives
The plotline of the knight of black knives also occasionally mentions an "ancient plot". I believe like many, that we can take what we know about the Night of Black Knives