I assembled this thing, and have no idea what its used for. It says to wear it and you will see things that you couldn't before, but everywhere in Firkraag's dungeon I didn't see any secret stuff. If its used to discover the Dragon sword and shield, then it works by just having it in inventory.

I just want to make sure I'm not missing anything. Is it used somewhere else? The suspense is killing me! ;)

you use it to see the final guardian of the treasure you're looking for (i think you can kill him anyway without it but he's tougher) - but i can't remember what the treasure is - i thought it was some dragon item, so it sounds like you've already got it . keep the mask anyhow - it protects against critical hits for those who can't wear helmets.

Didn't know about the helmet usage, that's nice. I just used True Sight to see that elemental dude, then whacked him. Thanks.