First up, full details that we can glean right now are available at Warhammer Community's two posts:
Defence of Ryza is a pretty straight forward description. Will you shatter the great Forge World or will you defend it?
Ryza was an important target for Horus and the Dark Mechanicum. It's a powerful planet and home to a major Titan Legion and Skitarii contingent. The new book gives us not only four new Titan Legions, but six Knight Houses and revised rules for creating your own Titan Legion beyond the White Dwarf rules published in 2019.
Wait.....Blackshield? Yes, you're reading that right. Blackshield Titan Legions are going to be a thing meaning we'll have some new lore to uncover. And that's on top of the new Knight kits that we'll receive, allowing the deadly Knights Acheron and Castigator to be built. Most impressive. The final part of the release is a new deck of stratagem cards that come from the new book.
We've also seen preview for four of the Titan Legions in the new book, including:
- Legio Honorum, the Death Bolts - A young, crusading Legio that took the fight to Horus's allies with some serious fervor.
- Legio Osedax, the Cockatrices - Decimated by the Dark Mechanicum this Legio is vengeful and has no problem with retaliation.
- Legio Magna, the Flaming Skulls - Reckless, these large allies of the Word Bearers and Sons of Horus loved using spearhead attacks much in the way that Horus Lupercal did.
- Legio Vulturum, the Gore Crows - A Legio whose existence is pretty much shrouded, these merciless killers used plenty of experimental technology.
This should certainly make Defence of Ryza and interesting book.