The fact that Diablo IV is coming is getting more and more confirmed by the day. In the Official “The Art of Diablo” by Blizzard Entertainment it says on the page of Lilith (Daughter of Mephisto, Lord of Hatred, the sister of Lucion and known to all of Sanctuary as the Queen of the Succubi) the following text:
Lilith’s debut in Diablo IV is a reimagining or form that is far different from her previous appearance (see page 236).
And #DiabloIV pic.twitter.com/yocnkQa5vy
— WeakAuras (@WeakAuras) October 26, 2019
Parties who have received the book in digital PDF file are missing a few pages, which may be that this has to do with Diablo IV