He discovered the old mage had been killed by cure on a book he had found in the ruins. Azzmere had been exploring the area for decades and had discovered that this region was once a powerful empire ruled by a king called Necronolis, who legend had it became a Lich. During the fall of the Netheril empire a thousand years ago, Necronolis' realm was shattered by a series on monumental earthquakes, leaving nothing but the barren region now known as The Fallen Lands.
Auran deduced that whatever the creature was it was probably left over from that time and the recent explorations had disturbed it. Eventually, he tracked the creature to an area of the badlands where ruined buildings poked up out of the broken landscape. The lining fast creature attacked him with its fiery breath which at first scared Auran because of his fear of harm coming to his highly flammable wing feathers, but he attacked it with his magically toughened long sword, which shattered on the creature - a short stubby frog-like creature.
This shocked Auran, as he had heard of creatures immune to non-magical blades which could be harmed by enchanted weapons. This creature seemed to be immune to all sorts of weapons. In the end, Auran started casting magic and the creature ran away seemingly frightened of the magic. Cornered, he managed to lightning bolt it and kill it. Later, he discovered it was some sort of Yugoloth, summoned from the Outer Planes and set to guard the ruins.
As a result of Auran's actions, the tower was granted to Fallow's Cross as reward and a small guard detachment was established here, especially after it was discovered that the symbol of Necronolis was on the Amulet for the Summoning Circle!