I plan on running at least the first 5-6 chapters of the Thousand Thrones (minus Chapter 2), having scoured internet fora of postings over the years and reviews and hacks etc, including useful ones here.
My take, turning on the real reason those elves are poking around the Crusade.
One of the “mysteries” of the Warhammer world is “what happens to the boys?” In Bretonnia, children with the gift of magic vanish often as babes. The girls reappear later as damsels but the boys are never seen again. Various theories of dark plots by the wood elves of Athel Loren are whispered, how they use the Bretonnians as puppets, the girls as their pawns and the boys…. Even these rumours do not dare do more than speculate on various wild possibilities.
Canon has never clarified this (to my knowledge), and I'm fine with canon leaving mysteries for different game tables to use.
Without revealing what happens to “most” of the boys, here is what happens to some and in particular one who is now known as Karl.
The wood elves have a couple of pre-occupations – keeping their bond with Athel Loren intact (it’s not a sure thing), protecting Athel Loren, fighting chaos (as the main threat to Athel Loren) and other threats such as undead. Many of the boys may go to further the first (part of mystery still) perhaps but some at least are used to further the latter two. Humans are handy bulwark/cannon fodder/guard dogs depending on metaphor. Guard dogs perhaps, as occasionally a keeper gets fond of one but only in that “good dog” sort of way. Humans are of course frail, easily corrupted things – weak instruments against Chaos often turned into instruments for Chaos.
A mysterious and reclusive kithband (the black ops CIA types, creepy/scary/extremists even to the other creepy/scary/extremist wood elves) has a special project. Some of the male children with the gift are suitable for a ritual that harnesses their gift and sets it permanently into a fixed pattern. They can then never channel magic as they become instead charismatic, very healthy, very lucky people (Karls– and thus reason elves particularly are less affected). This makes such boys, when they grow into men, into ideal champions against Chaos – leaders of men, able to rally the weaker humans. The arrival of a large cadre of these would spell the end of free-willed human society as it would become a demagogue-dominated military state dedicated to fighting Chaos – not a good thing if you’re a human really - an apocalypse of sorts in fact but hey, that's what you get having wood elves for neighbours. This kith band of elves raise and train (brainwash) the boys and then put them into a timeless sleep – gradually building up their “sleeping army” of champions against the day it is needed.
The Lahmia discovered part of this secret, at least the Lahmia queen in Silver Pinnacle did (she doesn't really know what the wood elves are doing but she knows they take the boys and make some of them special in this way). She found this as she searched for a vanished Bretonnian boy born under the signs prophesying the birth of the Scion which her divinations revealed to her would be a key to great power. That the Scion is a boy with magical gift who the Asrai have made a uberman is a promising start for the Lahmia Queen's vision. A kidnapping was orchestrated to bring the boy to the Queen. Most of the black ops kithband was slain, he was kidnappped (still a babe) and smuggled out via Bretonnia through Marienberg but fate turned against the Lahmia.
Pursuing Asrai caught up to the Lahmia and nearly all on both sides were slain. A lone Asrai (female) escaped with the precious child, fleeing into the Swamp – suffering from poisoned wounds. The mutants found her as she lay dying with the child. [So the record is of a dying elf woman with a child that appeared human]. Both sides received no information back from the confrontation and thus were unsure were to look to solver the mystery each faced – both fearing the child slain (though the elves feeling that better than discovered).
The factions are thus - Chaos Cultists who found out about a strange child when the Shallyans started making inquiries about Karl, Lahmia vampires who then got onto the trail of their lost merchandise once the Crusade became public (and rival Strigoi vampies etc.) and last arriving, the final suriving members of the Black Ops Kithband. Behind all of this, there is still the question of the Scion and Nagash of course.
This allows first few chapters mostly as written I think (I'm less interested in the Black Witch/Kislev aspect of campaign).
Does anyone see any gaping Warhammer-canon holes in the theory? Any ways to leverage it even more in the campaign?