Daemonic Frenzy is a generic notification informing the player that all rifts to the Chaos Realms have closed and armies that came forth will attack soon in The Realm of Chaos campaign.
In-game description[]
The rifts have gone. The Daemonic hosts that crossed the maelstrom through them have lost their link to the Chaos Realms. Without such power to sustain themselves, the hosts will quickly dissipate, so want to take as many souls with them as possible!
Ready your defences - the Daemons from the rifts attack!
Strategy[]
In Daemonic Frenzy, Daemonic armies will also attack factions belonging to the same Chaos God. For example, Rapturous Excess armies will start attacking Seducers of Slaanesh, even though both factions belong to Slaanesh.