Okay, so after searching through the forums and faqs, we all know that it is impossible to both keep the illithium for the MoD and complete the Sarles quest - at least complete it with as much XP as you get for giving him the real illithium. So the only possibility is getting it back from him after giving it to him. As far as I can tell, he remains in the Jysstev house indefinitely (at least for chpts 2-3). He's carrying the ore, but it can't be pickpocketed. So it seems the only way to get it back is to kill him. But that causes reputation loss. So, is there any way to kill a single non-hostile NPC without reputation loss? About the only way I've found is to summon a demon, who will kill him without reputation loss. The only problem is that it must also kill the other three people in the house since they turn hostile when he is killed. That doesn't cause reputation loss either, but I'd like to keep my cold-blooded murders down to a minimum :) . I've been looking over the mage and priest spells to see if there is some indirect way to kill him, or some way to alter him so that he can be killed without reputation loss. If I do have to kill him and everyone else with a demon, are the Jysstev's needed for any other quests besides Sarles and the Hidden?

Well, you could kill the demon after he kills Sarles.

Personally, I hardly ever get the MoD+2. Even though the Negative Plane Prot. is a nice bonus, I just don't see the attraction to it. It's not like undead are particuarly hard to beat.

You could also simply use protection from evil on the others iirc.

I don't think Mace of Disruption +2 is worth all the work you are having. But if you want it...well, the Jysstev State does have another quest (SPOILER!!!!!!!!). Is the one about the Hidden and the diseased girl, is the subquest of Jan Jansen.
Use Protection from Evil on the others in the house as Kemcon said and then kill the Demon, or simply use SK to give you the damn Illithium and do yourself a favor of "loosing" a good amount of gold from your pocket (just for conscious...pretending you had bought the illithium somewhere else)for nothing...like buying a lot of potions and letting them on the ground. :D

you could get the fake illithium from the person in the promenade. Then get the real stuff. Take the fake stuff to sarles who will leave in a strop because it's fake, but the church will still accept it. You can then keep the real illithium.

afaik the house is used for nothing else apart from Sarles and the hidden

I forget if you use the fake stuff... do you still get the Helm of Glory?

Yep, I think you do, haven't done it in a while. did it first time I played through. Not done it since though :hmm:

usually skip that quest because I dislike doing the unseeing eye.

Summon a few things and have them attack eachother so that they go on a rampage. -JMuch easier to manage than a berserk, fire-ball throwing demon.

I confirm they give you the Helm. You can even pickpocket it before.