After talking to Marte's ghost, my party became insane. I used the helm of serenety on all my caracters (after the fact), rested them, time and again but at no avail. I can't find a cure, for nobody sales "potion of cure insanity". Any ideas of what shoul I do. Thanks.

You have to have one of you party wearing the helm, and then that character takes the object in their inventory. If you do that when you get the item, any insanity quickly goes away. If you wait longer to do this, you can't cure them, from what I have heard.

So, do you mean that this is the end of the road for me? Because I wasn't wearing the helmet, I have to go back and do it again? This is what I mean about this game. STINKS.

I deliberately walked aroud insane for some time (with my fighter/bishop duo, when the bishop was dead). After wearing the helmet, and a brief rest, it was gone.
If it has ever been a problem, its fixed by the ptaches.

With all respect Weraboar, the same thing that I told Ziggurat. This game "STINKS". When do they give you a hint that you have to be wearing the helm before you talk to Marten? Even If they have given you a hint, if the results were going to be so catastrofic, the game itself should not let you do it.
Asta la vista amigos.

I think the marten ghost will tell you to wear the helm first. but that come a bit too late already since you are already there.

In this game, I have found that every puzzle has some hint but you have to be thorough, trying everything. When you get the Helm of Serenity, the Shaman has warned you about it. He does not mention madness directly, but it is said to be a protection of some kind for the Destinae Dominus. Marten made it for you to wear, to prevent his mistake from happening to you. It is easy to forget these things, ten or twenty game hours later, when you are fulfilling a quest. I missed it the first time through. That's why I save "early and often". That is a mantra for difficult games like this. Keep a reserve save before big events. And the game does not stink. Most good CRPGs have a difficulty level that people don't have patience for. The Might and Magic group got away from that, so some might prefer easier games. I do like the M&M series, but they got easier as the progressed. My 2 cents. (M&M 2 was pretty hard, they went more soft after that, perhaps because of similar complaints...)