I found the Devils Axe, and equipped my Barbarian with it. Of course it was cursed, but it is an awesome weapon. It was going to cost +-20 000 gold to take it off the character, so i decide to leave it and build up his axe skill (he did not have any). So far it is working. However, it is in the palce that the underwater breather would go. Is it worth removing the axe to equip with the breather, or should I just leave him with the underwater helmet? Has anyone else found any other great weapons? I found the Robinsword, but unfortunately did not repair it often enough, and it broke. I have also found a number of nightshades.

An option that you have is not to take your barbarian along with you to the underwater city - leave him at the inn. I would only recommend this is you have the Create Portal, Teleport and Call of Home spells so that you can gather him up after you are done with the city.
There are a number of good weapons in the game - Robinsword, Nightblade, Axe of Runes - and not all of them are cursed (imagine that!)

Wyv