We'll see a new Khorne Codex this week

An anonymous source on Faeit 212

Codex: Khorne Daemonkin
120pg hardback Codex. Rules for fielding a combined force of Khornate Chaos Space Marines with Daemons of Khorne.

Warhammer 40,000 Datacards: Khorne Daemonkin
45 reference cards; 36 tactical objective cards; and 9 large-format ‘Blood for the Blood God’ cards.

Khorne Daemonkin Warband
10 Chaos Space Marines; 5 Possessed Chaos Space Marines; 5 Chaos Terminators; a Chaos Helbrute; 3 Bloodcrushers of Khorne; 12 Khorne Berserkers; and a Resin Herald of Khorne.

Also New Citadel model cases
Skirmish – 100 infatry size case
Battle – 200 infantry case
Crusader – 400 infantry case

These aren't rumors because there already links for the new products:

You'll still get a 404 Error, but that's not the point.
Try to use: http://www.games-workshop.com/en-GB/...-daemonkin-eng
You'll be redirected to the correct page