An ample writeup of this shadow can be found at http://www.dkcomm.net/rhea/AmberRPG/UnicornSeishi/BeyondGoldenCircle.html#Mystara on the official campaign site.
Home to the The Corunglain Free Rifle Company, Mystara was the destination of many groups all involved in an effort to recover the spikards and the Dragon Staff once possessed by the now fallen Gaunt Man.
As it turned out, the mysterious Kuonji Ukyou had already managed to snag the Lion spikard, which he claimed to be safekeeping. And after a long and arduous struggle through a booby-trapped pyramid, the Amber contingent found that he'd also managed to swipe the Dragon spikard as well, having left a false spikard signature behind to make them waste time and effort to do so. (This has not exactly endeared him to the Amberites.) The staff has been recovered, at least, taken from the hands of the Gaunt Man's henchman, Ancalgon?.