I haven't been reading too much from the Black Library for a bit, but whoa did this catch my eye. Mortarion and Guilliman going head to head. Im in.
I did not see a release date for this yet, but if you haven't read the previous two books, they will be re-released soon.
via WarCom
Guy: This is the climactic conclusion to the whole series, the moment we have been waiting for! Guilliman faces his brother Mortarion on the garden world of Iax, which the forces of Nurgle are busily transforming into a daemon world named Pestiliax. Most of the planet has fallen, but a few enclaves hold out, and it is at one of these that Guilliman and Mortarion will finally come to blows.