They're killable? You said Moringotho might have done it -

They're probably killable. Few absolutes. I've never heard of it being done.

A spectacularly successful practitioner a thousand years ago got most of them sealed and locked up, somewhere. Now they only really get to earth when someone summons one, which happens more often than never because they're powerful and capable of dealing. The anti-demon strategy is pretty much to find diabolists and make them stop.

And if she got here on her own, she'd have no particular reason to bargain with Melkor?

She would, if she wanted to destroy the Trees and couldn't do it on her own. It's just that bargaining with non-practitioners doesn't occur to most Others and demons don't seem likely to be exceptions.

If she's a non-demon Other I'll be really relieved.

You haven't seen a Vala, right? Have any practitioners? They might strike an Other as worth bargaining with.

It's not a question of worthy. Noticeable might be closer. Others don't typically sense the world the way we do. An ice elemental might see cold, and the terrain causing one shape of the ice formations rather than another, and so on, and then "thing the practitioner says" gets arbitrarily tacked on to the end there. He wouldn't have that.

Though it would fit with the weird distortions around Melian and the invisible Maia or Vala at the trap. Spirits are paying some attention at least...

If it's a demon what do we do about it?

There are defenses. I don't know them.

The rules of thumb should still apply. If an Other has a theme with a direct opposite, it's probably physically vulnerable to that. Light sounds like a good bet. If it's really powerful that won't do more than inconvenience it, it did manage to get to the Trees after all, but it's something. And this symbol, she sketches out the Seal of Solomon, comes from the guy who neutralized a lot of them a hundred Years ago. Now it's more general-purpose protection from a lot of Others including most demons. Standing in this diagram charged with something, usually blood, can get you from dead to cornered.

Mostly what we do if it's a demon is hope we don't have to face it. Where was it last seen?

Valley of Dreadful Death. North of where Doriath's vaguely supposed to be.

That's potentially in the demesne ritual's hailing range of Doriath. Melian mentioned it when I asked where there might be Others coming from...

So making Doriath a demesne might require a fight with a demon?

It might require giving Ungoliant a chance to challenge Melian. If Ungoliant is an other and if she's in range. It wouldn't have to be a fight, but if it's a demon there are no good options.

Melkor betrayed her and they had that fight, can she be convinced to get him back for it?

No idea.

If she's not a demon then the demesne challenge is a weak negotiating position to start from, since the stakes if you win are "the challenger goes away." If she is...making deals with demons is the worst karma, and for very good reasons.

I'll take your word for it. Can the bad karma affect the Enemy? Of course, he probably has bad enough karma anyway...

Good point. Yeah, using demons would absolutely be a way for non-practitioners to get karma problems if it ever came up.

Is betraying a demon better or worse than keeping a deal with them?

For a practitioner worse. You'd be forsworn and then it or anything else would be allowed to eat you. For a non-practitioner who somehow landed in a deal, probably better. It's the sending it off to do things that's the problem, and that would have already happened, but non-enforced lies are on a way smaller scale than anything involving demons.

Enemy's not retroactively forsworn if he happens to figure out magic, right? And the karma for past deeds doesn't get even worse? 

Both true. And he probably isn't going to negotiate with Ungoliant again.

Very much doubt it. 

If Doriath's currently receptive to a diplomatic envoy, do they want us to just walk around in the woods until they decide whether to extend an invitation, or what?

I think they've already decided they will. So just until they've verified that no one involved works for the Enemy. I'll tell you where the borders are but I doubt it's possible to simply walk into Doriath without Melian actively allowing it.

That's what our intelligence had suggested also. So we'll just send some even-tempered people who can swear to things and will appreciate being in a proper Elven kingdom again - he sighs longingly - well, appreciate it unusually much... and hope they're merely kicked out when the truth comes out.

They won't be executed or anything. Though they might still be kicked out even if Doriath happens to be under attack right then.

And to be fair to Doriath it's not as if they'd have particularly appealing other options. We'd kick people out if we found good reason to think it wasn't safe to have them around.