The Fury Crossbow
This artifact is the second easiest, and worth the trouble.
The Pit of the Wyrm
Learn the crossbow's location from a priest in Shayder. The dungeon is near Bremerton. Enter and read an interesting journal to the North. Then follow the obvious path until you get to an area with Mung Slimes. The stairs to the second floor are here. The second floor is harder. There are Mung slimes, Dark Wyrms, and later, Ghouls. Follow the cave around the outside untill you get to the Southeast part. Now go to the Northwest into a pit. Follow a secret passage ther into a crypt. The lever opens the Tomb of Sarios, and the cryts to the North. Go into the tomb (The building to the South.) The first room is a puzzle. When you step on a purple tile, you take damage. If you step in the wrong place, you go back to the start. Just figure out the pattern and you'll make it. The next room contains the Fury Crossbow.