Avernite - I think you are essentially correct. I believe a coalition of gods from many pantheons got together and used the Stone Table to transfer a LOT of power into the Sidhe. But not so sure it was murder, rather I think it was sacrifice. I think it was done not to detriment the gods, but to help them. WOJ is that the Sidhe were given power by agents who thought their influence in the mortal world was waning.

Bad Alias - I think the Gaia theory is more likely here. I think that because of all the different gods and goddesses pouring in their power, that is how they became what they are. But I think they were always important in the various pantheons (Moirae in Greek, Norns in Norse, Devi/Kali/Parvati etc) and then gained additional significance and power.

Strengths
*  Fairly low powered god.  The combination of Lady, Queen and Mother is collectively equal to a strong god like Hades in power.  The Mother has the lion's share of that power, so Mab by herself has to be fairly weak in the god power scale.  I would argue that the very weakness of her god power is a strength as she suffers much less restrictions on the use of her power as compared to the more powerful gods.  The universe as described clearly has rules that severely limit the more powerful beings.  The Mother must be far more constrained than the Queen and the Lady should be less constrained than the Queen. 
*  She can hear things spoken at night, especially if her name is spoken.  Great source of intelligence
*  She commands the winter fey.  Mother may be stronger, but the queen rules day to day operations

Weaknesses
*  Mab cannot harm a mortal directly, but must wait for them to make themselves vulnerable (via a deal) or use the Winter Knight. 
*   There are MANY other powers comparable to Mab out there in the universe.   Her attention must be split to counter many of them and/or make sure their agenda does not hurt Mab's agenda.  For example, the entity behind the "worshipers" in the molly short story has nothing to do with the Outsiders, but was still a threat to Winter's interests.   Even though the Outsiders are clearly making a move, Mab cannot afford to ignore the other threats just in case they are acting while Mab is distracted. 

Lots of theories in there - I am curious about where you get your ideas from though. So let's unpack.

Mab is a low powered god - where do you have reference to this? She is clearly stronger than retired gods like Odin and the Lords of the Outer Night. In terms of your scale and the god you have compared her to (Hades), are you saying he is as strong as the Mothers (and by extension, an Archangel)? Because I have yet to hear of any evidence to support that. Archangels, and beings of their level (the Mothers, the Walkers etc) are beyond mere gods like Hades. But I am open to a discussion of an alternate point of view.

I don't believe that her power works like Anduriel's, in that she can hear all things of the night. Her title as Queen of Air and Darkness, is more to do with the human elements (reason and savagery) than the physical phenomena. Which isn't to say she has no influence (she rescued Harry from the cold dark waters of Lake Michigan) but I think this ability has never even been hinted at in the series. Her ability to hear her name is more to do with being supernatural, even Toot-toot has that.

Mother Winter serves more like the Chair of the Board, the ultimate ruler. She doesn't do day-to-day operations as she has duties and concerns that are much higher and more complex. She is more akin to a force of nature, than merely a steward of a role. As Jim says, you just obey gravity - duh.

Mab may not directly be able to harm a mortal - but she doesn't need to. She has all those other Winter Fae for that. Plus a Knight.

And the worshippers were worshipping a "sleeper" something that the Outsiders wanted released...

SK - We don't know that humans CANNOT be infected either. We only know of a few infected being anyway.

forumghost - I thought similarly for a while, that Maggie is behind a lot of this and was on the original team of rulebreakers. But. I also wondered if she merely, in her activism, came across more extreme types.

I think there is an old WOJ about the Jade Court very actively not being involved, and might only appear in the BAT. But who knows, Jim does change things up.

But yeah, definitely the Senior Council and most of the White Council. The Fomor, the Fae, the White Court, Marcone are all pretty much guaranteed. Possibly Mavra and whatever remains of the Black Court. I highly, highly doubt the Denarians considering the last book. And they tend mostly to show up every 5 books so probably not until the very last Case File. Ferrovax is a distinct possibility, considering his presence at Bianca's ascension. Incredibly powerful being shows up at some schmuck Vampire thing? Probably doesn't bode well - and is highly significant. Maybe the other dragon perhaps? I also hope Drakul finally makes his big entrance, but we'll see. I suspect some Monoc Securities presence, plus svartalves etc. Would be fantastic to see any other interesting signatories, such as the semi-divine immortal shapeshifting guru from the Ukraine.

And of course, even if they are not announced as being there - the Black Council/the Circle. They will definitely have a presence there. And will stir things right up. I wonder if we might even see Cowl and Kumori - we are actually due to see them. Whether they will attend the actual talks openly is another matter.

The whole Faerie Queens = Hecate thing is just a theory. An interesting one, but by no means the only one. And it has never been confirmed.

What everyone always seems to forget is the sheer Power of things like Uriel. He is so strong he doesn't do contested violence, he has terminated galaxies and even whole universes (WOJ). Mother Summer and Winter are at the same level, and so apparently are the Walkers (HWWBh and HWWBf). But they are all limited because of their extreme might, and so can only use that incredible power in very specific ways at very specific times. This is all WOJ. And lastly, Uriel is considered a Senior Vice President of Creation. Assuming TWG is the President and Chairmen, I really highly doubt Hades and Hecate are at the same level. There are SO MANY gods. Thousands, possibly more depending on the limits Jim has set. There are only two Mothers, three Walkers and five Archangels. That tells you something right there.

And one more thing, there is a WOJ about how the Fae are agents of those whose influence was waning in the world, and so poured a whole lot of power into them in order to maintain that influence by proxy. This hints pretty strongly that many of the old gods put their power into the Fae in order to make them much more than what they were. This goes a long way to explaining their many links to the various religions and mythologies. There was a very interesting WAG that it was Hecate who all the power was poured into, but she was split in two (Summer and Winter) and the Queens are just different aspects of the original being, and the main bit that is left is Mother Winter (on account of the fact she has never changed). But that too is just a theory.

What is clear enough, is that Hades is not at the same level as the Mothers, and therefore cannot be as great in power as all SIX Queens combined. That would be insane. He would then be stronger than two Archangels combined plus extra. It isn't impossible I suppose, but considering everything we know about Power in the series and the various beings, it just doesn't add up.

Also Hades hasn't faded, he isn't like Vadderung. He simply is less involved - by Choice partially but also because of the balance of powers. See the WOJ about sleeping deities.

Morriswalters - Mab, and I suspect many other beings have some form of Farsight or Scrying etc. This is not the same thing as being able to hear and observe every thing that happens in the dark. Not in the same way Anduriel can. Don't you think that would have been revealed by now? No. It is more likely that when she chooses, she can try and observe various events as they happen (and perhaps see into the past and various possible futures, to some degree). Vadderung, Leah, Uriel and others have all shown the ability too, and I suspect they are far from the only ones. Hell, even Harry can view events happening from beyond himself either by scrying (using Little Chicago) or even through premonition.

This, while somewhat relevant to the topic, feels like a diversion from the OP. And while I am sure it is important as a discussion, let's stay on topic if we can. This is starting to feel like it might approach an issue, which does no one any good.

I think Jim has dropped a few hints on this, but unless I am much mistaken I don't think this idea has been actually floated.

Any being becomes vulnerable to Nemesis infection via being too close to Mortals and the Mortal World.

But I think that only applies to beings that are not multiverse spanning - Archangels, Angels, perhaps the Mothers (guessed but unconfirmed). But the hint is in this WOJ:

Mortals, in their own possession of free will, have a tendancy to influence beings who don’t have it, in one way or another.  I suppose it’s entirely possible, for example, that too much association with mortals are what changed Aurora, former Summer Lady, and gave her a determination to destroy the natural order in an effort to change its very nature–for the better, true, but it would never even have occurred to any of the other Queens, Mothers or Lady that such a thing might be, until it had already happened.  It isn’t in their nature.

But perhaps I’ve said too much.  I’ll shut up now.

So this first part I have highlighted pretty much gives that hint. We are pretty sure Nemesis is what corrupted her, but how it was able to get past her guard might be the fact she was spending too much time with mortals...like Elaine Mallory (make of that what you will...was it really chance she ran to the Summer Court...?)

And secondly, what is also really interesting is that Jim seems to be saying that the destruction of the natural order would be a GOOD thing. Huh? Yet that second part I have put in bold seems to suggest that destroying the natural order might have been for the better. Could it be that the Faerie Courts are not as good for reality as we think? Could Nemesis serve a purpose?

Now of course, that is somewhat unrelated to my opening but it is important. And I am aware that this doesn't really address how Mortals become vulnerable to Nemesis, unless of course by their very nature they are always vulnerable. By being able to Choose to do something, to shape themselves and their destiny via their Choices. I think so, and I think it is the same reason Immortals would otherwise not be vulnerable, but become so.

And it makes sense too! Lea spent too much time with Mortals, especially just before she received Morgana's Athame. Her immune system was down you might say (draws a nice parallel from Winter being Realities immune system, and the Outsiders being the virus). Maeve spent a lot of time with Lloyd Slate and Lily etc justs before Lea got to her. Cat Sith spent a whole bunch of time with Harry before HWWBf got to him.

Thoughts?

Mmm yes I think it is definitely more than merely just taking away TWG's toys. I suspect there is real power involved, and that the war is more of a cold war between Heaven and Hell. Souls as a power source has been done before, and I am sure Jim will have an interesting take on how it works.

Snark Knight: Not sure that the Multiple Man act was all the different versions of Before coming together (unless of misunderstand your comment). I think it far more likely he is simply strong enough that he can be a sort of gestalt consciousness, inhabiting many vessels (which he perhaps creates himself). Only mortals would be so limited to operating the one meatsuit, I think stronger beings could have many avatars being used simultaneously. Which is not to say mortals don't have that potential, but our earthly physical limits would likely prevent this. Lea gives some hint to this when saying that the brain is not the only storage facility for memories, in fact often a poor receptacle for such things. The body seems to be an actual limit to the full potential of a Soul. Not sure what you mean about the "there-but-not-there" behaviour...were you referring to his power being impossibly deeper than Mab's (the photo of a sculpture vs the actual sculpture itself)? If so, I totally agree. But I think it is because the Outsiders only ever put a portion of themselves into Reality, they have more "essence" than is truly comprehendable and compatible with Reality and so are limited by whatever amount of themselves has been "invited" in. Think the Void Lords in WoW or the Daemons of Chaos in Warhammer/40K, or the Outer Gods in Lovecraftian Mythos.

Pretty much bang on I think. It is very much an everything is connected game. Which lends weight to the conflict between Heaven and Hell - each individual Choice, each Soul, is incredibly valuable.

I think it is a matter of the degree to which each thing affects the other things. I mean Mirror Mirror couldn't happen if there was no effect at all.