Did anybody else catch that hidden message? Coupled with the name distortion, I wonder what that means...
He already knows exactly where we are. Remember the memory "tag" he left on the golem? we can be 99% sure he's the one controlling the golem in the forest.
The first time he contacted us, we saw a dream of the pool we used to fish, back at the elven forest, along with some necromantic fish. Right after we left our home and experienced the stress of telling Omo about necromancy. If the beginning of the dream was created by Fale, then that would mean he has access to our memories and thus has no need to ask us questions. He should had known much more about us and the elves.
I'm pretty sure the first part of the dream is either related to some other entity, perhaps some god or other magical entity, or is just that: a dream related to what we are experiencing, what is making us anxious, combined with whatever necromantic energy or spell trigger is making us susceptible to being contacted through dreamscaping. (No idea what the trigger could be? Maybe it's related to the people close to us? Them knowing about us being a necromancer? Them getting hurt? Maybe it's just related to our emotional state? Maybe a coincidence?)
I'm inclined to think it's the second thing (perhaps combined with a bit of the first thing), given what Nym said: "I was dreaming and now I'm here." meaning that the first part was a dream, or something like it, while the second part is not a normal dream.
Irrelevant, but the fact that we are participating/being subjected to dreamscaping while inside a sanctuary is also an important piece of information. Either dreamscaping is not stricly Necromantic or it occurs through some dimension not covered by the sanctuary (perhaps our minds travel to another plane like the ones Eko mentioned while dreaming?) or it occurs because of some power for which sanctuaries are no problem, like for example a god.
Or the spell was powerful enough to break or evade the sanctuary, but I doubt that. Still, we should check the sanctuary tomorrow, see if it is still up or if it has failed.
Given that, he also already knows Omo's state and that we would want to restore him. The truth is, we have almost no sensitive information to be afraid of leaking to him.
That would be true if you are suggesting he already has access to all of the contents of our mind, but not otherwise.
I'm not suggesting we make a "deal" or pact with him. Just the opposite. He just acknowledged that we walk different paths and that it's ok with him. And he offered to give us knowledge that can help us down our path. As long as there are minimal strings involved, I say we take it, because we're really in a bind here. As long as it is clear we aren't going to be helping him along his "world domination" schemes. But skitting around the bush isn't going to get us any of the help/info that we need.
In the end, both he and us want the same thing: the world safe for Necromancers. He thinks the only way is world domination. We're looking for a different way, which he said he's ok with. The way I see this campaign, the objective isn't really "defeat the evil necromancers," but rather "find a way to bring peace to the world." (Which cannot happen as long as everyone kills any necromancer on sight)
tldr: He's not saying we join forces. He's offering us help as a third party. Take the help but make it clear we aren't going to conquer the world for him. Our goal: finding an alternative to conquering everyone that lets necromancers live safely.
Does he really think the best way is world domination? Or has Morka brainwashed him into thinking that, perhaps using whatever dark emotions and bad experiences he has to convert him into a fanatic for his cause? I mean, the world is pretty large, it's hard to think one man would wake up one day and say "Oh, I just happened to be a very powerful mage, one of those that rarely occur. And I'm Death-element-aligned. So I'm going to raise an army out of my friends and kill and/or enslave
everyone on the planet just so that me and a couple of other guys have fun.", let alone so many during the time after the Golgothan war. It's much more likely that they were contacted (or even created/empowered in part) by Morka and then manipulated into trying to conquer the world and causing more death. Or, I dunno, whatever else a death god would want.
Anyway, if those are his intentions, then we can easily ask him to prove them. Say that we are not interested in world domination. And that while we may have no reason to oppose him, we have no desire to help him either, no reason to indirectly risk hurting people who have not hurt us, no reason to risk him hurting our friends or family, all those people we know long enough to know their daily routines, people we have spent all our lives with. So we won't give him any information about those subjects. But we are willing to talk about the basics of necromancy and magic in general. And that if helping another necromancer is all he cares about, then he should accept that and help us, thus earning our more of our trust. And then we can start our inquiry but in such a way that we reveal as little as possible.
Not really the best way to go about this but better than laying all our cards on the table.