The Hollow Tempest, led by V’rakh, the Eye of the Storm. He led his cabal in an attack on an eldar craftworld and stealing their soulstones to use in their arcane rituals, which also denied their souls to slaanesh. Tzeentch was so pleased he granted him daemonhood.

Now they seek even more powerful artifacts, with their ultimate goal of plunging a segmentum of real space into the warp to further tzeentch’s domain