There has been a lot of speculation about some of GW's recent rumor engine images that appear to be undead-themed. GW's "Gridiron and Glory" reveal show didn't have anything about those rumor images, so the speculation continues. I'll throw my hat into the ring with my predictions:
The general consensus is that this these leaks herald the release of a new Soulblight battletome for Age of Sigmar. First off, I'll just say that Warhammer Underworlds and Warcry have all but ruined new army speculation for me– Even the largest collection of previewed imagery may end up being nothing more than four or five models in a single Underworlds warband.
Case in point, this rumor image is CLEARLY an Ossiarch Bonereaper model, but GW isn't in the habit of making add-on models for existing battletomes; they usually add new heroes to upcoming battletomes. So this is likely going to be for an Underworlds warband. Certainly not part of a Soulblight release.
This image has been part of the Death speculation because it's a model playing a bone flute. But it looks like it has three fingers, same as a Nurgling, something that might accompany the Sloppity Bilepiper, who also has bone-instruments. The arms appear to be sculpted as a single piece, common for small bits like Nurglings. So, I'm discounting this image from the Death pantheon as well.
Now, we're getting to the good stuff. This looks like a Flesh-eater Court model. A ghoul character or something of that nature. The old, notched sword, the black fingernails make it a Death model. None of the models in the Flesh-eater Courts army are equipped with proper "weapons" however– they mostly wield bones and rocks, but models in the Underworlds warband do use metal weapons. (There's even a ghoul with meat hooks!)
This hand with the hook is probably another Death model. Maybe a ghoul, but the wrinkly skin could be a zombie. There's even what looks like it might be a hole in the skin at the top of the image. (God, please make new zombies, GW. And don't make them $40 for one sprue of 10 single-pose push-fit models.)
This halberd also has the hallmarks of an undead weapon– pitted, dark metal and a wicked shape.
Then, we have this pair of images– Ornate swords with what appear to be blood-drop iconography in the top image. Good candidates for Soulblight.
So, I began to think that if these aren't just Underworlds or Warcry warbands, we might get a new battletome that combines Flesh-eater Courts and Soulblight the same way that the Orruk Warclans book let you field an army of Ironjawz or Bonesplitterz, or combine the two as "Da Big Waaagh!" How cool would that be? A new "Vampire Counts" battletome (maybe call it "Vampire Courts") incorporating the Flesh-eaters and the Soulblight Courts, able to be fielded as separate armies or together as they once were.
But these aren't the only Death-themed rumors– Crows and keys are often used in Death imagery:
And there's this hand with the skull. The flames(?) coming off of the skull would mean that this is a wizard of some kind, maybe a dedicated ghoul sorcerer? The hands are a little long and spindly to be a necromancer. This could also be a Tzeentch daemon; they have long, clawed fingers like that. The flesh coloring is a little dark to be a ghostly Nighthaunt model. The cloak of stitched-together skins could likewise fit with Death or Chaos. (It would be a good candidate for an updated Heinrich Kemmler, but is GW really going to resurrect a character that hasn't had a new model in over 20 years and was left behind in the Old World? "He's dead, time to move on, brah.")
Edit: The skin was already confirmed as the cloak of a Chaos Warrior. Thanks, Warboss Kurgan!
This brings me to my next point of speculation: We need an update to the Legions of Nagash battletome. Even though it was written for the 2nd edition of Age of Sigmar, it was actually released prior to it, and has a lot of information that's out of date. The further we get, however, the more I fear that the Legions of Nagash might get dropped altogether as an army.
A lot of its content is already in other battletomes– Nighthaunt and Ossiarch Bonereapers. If we get a new Soulblight battletome that includes the vampire units, Deathmages, Deadwalkers, and maybe Deathrattle units, Legions of Nagash will be mostly redundant. In that case, I'd also expect to see units like the fell bats and bat swarms eliminated. Unit options like the winged vampire and mounted wight king would also be cut so GW could finally retire those decades-old models. (I've been saying it for a couple years: If you haven't already made them, don't get carried away converting wight kings on skeletal steeds or vampires with bat-wings; once GW stops selling those old models, those options will no longer be included in future battletomes.) They might even tout the Anvil of Apotheosis rules as being the "perfect way to include those [now-obsolete] models in your narrative armies."
We've also got these tidbits, including today's rumor engine image of a wing with some chains and a skull. This leg might be some kind of cool werewolf, but it feels a little too clean for something that's undead. The architecture that it's standing on does resemble the bit that the crow is perched on, though...
That wing strikes me as more of a Chaos item. The chain has "pointy" links, and most of the Death models have oval chain links. The wing could also be part of the same model as these teeth. That doesn't quite look like bone, however, which further convinces me that it's not undead.
But in the end, I think my official answer to the question of whether we will be getting a new Soulblight battletome or an updated Legions of Nagash battletome is... "Neither." No Soulblight book, no new Legions of Nagash book (and no Vampire Pirates either, sorry).
I think all of these previews are just leading to models that will feature in one of the Broken Realms books that focuses on Nagash or another Death character. The Broken Realms book will serve as a patch for the Legions of Nagash battletome, and will include some new Soulblight and Flesh-eater Courts units and characters. Or who knows? Maybe those previews will turn out to be just another Underworlds warband...