Here are two pictures, one from the last Tomb King book, and the second that was just released with latest White Dwarf. Both show what looks like a construct in the background. Since this is artwork from the latest Fyreslayers in it, could we see some new Undead coming soon?
Please remember that Tyler is just calling out what he is seeing. This is not really a rumor, but more of an observation.
via Tyler from Mengel Miniatures
The first picture is from the 8th edition Tomb King book, the second is from the White Dwarf with the Fyreslayers in it. That's clearly the exact same statue/construct. I'm betting it's the unreleased Hierotitan that we have heard has been done for awhile now. I wouldn't be surprised if we see it finally released whenever they get around to Death in AoS.