Well, there'll be Slaanesh forces in the upcoming Direchasm expansion for Warhammer Underworlds. But they won't be down there alone. Mayari's Purifiers will be looking to expel them from this plane of existence. We get a look at them in this preview.
From the preview:
Hailing from the Great Nation of Ymetrica, Myari and his kin descend upon Beastgrave convinced that they alone can end the hunger of the living mountain. This four-aelf warband is perfect for fans of the flex-style play, as they’re able to grab objectives, kill enemy fighters, and cast magic.
They also introduce a new mechanic into the game – aetherquartz counters. Each fighter starts with one of these counters that can then be spent to give a re-roll for attack, defence, or casting rolls.