Now we have the still images that are flashed by in this video. This is definitely Chaos Daemons. I can't see them doing a whole video for a release without a codex.The must be updating the entire codex in a White Dwarf. Talking about throwing us for a loop here.
In August, the immortal legions of the Ruinous Powers - the Chaos Daemons - will pour forth once more from the Realm of Chaos to drown the Warhammer world and the galaxy of the 41st Millennium beneath a tide of blood and destruction. Even now, mystics are assailed by nightmarish visions of horror and death, the fractured minds of madmen echo with sibilant whispers, and the doomed clutch symbols of their weak gods closer to them.
A host of incredible new Citadel miniatures for both Warhammer 40,000 Chaos Daemons armies and Warhammer Daemons of Chaos armies will soon be released upon mortal battlefields. All will be revealed in July here on the Games Workshop website and in August's issue of White Dwarf magazine, so keep an eye out for more information.
OK. Finally with a little bit of caffeine I was able to catch the flashing images. They are definitely Chaos Daemons of Slanaesh and other daemons in the pics. Here is are the still shots via Hooligan Seth on GW-Fanworld.net