The universe of the Hundred Halls involves many supernatural creatures. Some of them are inspired by my decades of playing D&D or other times my extensive SFF readings. The Mystdrakon is first encountered in The Reluctant Assassin series and later makes a reappearance in Animalians. I created the creature based on an old book called The Legacy of Heorot. In it, settlers land on a planet far from our sun and encounter a dangerous creature they call the Grendel. The story was wonderfully written and at one time it was being made into a movie, but alas, it never made it that far, but the creature never left my imagination.
As I mentioned before, I draw inspiration at times from playing D&D. But in this case, I wanted to flip the script, and create a monster stat block for one of my creations. The mystdrakon was the first creature that came to mind. I hope you enjoy it and please let me know if you use it in one of your games.