Thalzar was a wizard from Crandor. When Elvarg, the dragon beneath the island, awoke, she destroyed the settlement. The survivors fled to the mainland, and the map to the island was split into three pieces to prevent anybody from travelling to the island. Thalzar took one piece, while his fellow wizards Lozar and Melzar took the other pieces.
He was very paranoid, taking great care to hide his piece of the map and entrusting its location to the Oracle. He placed his piece in a chest with a warning inscribed in the chest lid, sealed it behind a magically locked door in the Dwarven Mine, and gave the Oracle its location. She reveals the location through a riddle, indicating that the door is opened by using a wizard's mind bomb, a piece of silk, a crayfish cage and an unfired bowl on it.
He died at some unknown point in time. His last recorded words were:
Here, I rest the map of my beloved home. To whoever finds it, I beg of you, let it be. I was honour-bound not to destroy the map piece, but I have used all of my magical skill to keep it from being recovered.
This map leads to the lair of the beast that destroyed my home, devoured my family, and burned to a cinder all that I love. But revenge would not benefit me now, and to disturb this beast is to risk bringing its wrath down upon another land.
I cannot stop you from taking this map piece now, but think on this: if you can slay the Dragon of Crandor, you are a greater hero than my land ever produced. There is no shame in backing out now.