[X] Upgraded Malice. While Malice grows stronger, he is merely a peer to the Four, as he has concern over having his existence overtaken by the Darkness he's calling upon. Chaos Four become ChaosFive, with all that implies.
[x] Sealed Away. The Four cooperate long enough to seal Malice away. Chaos Gods start nudging large quantities of Orks and similar threats towards you in 5 Turns. Xenos polities have a far higher chance of becoming hostile and/or Chaos corrupted.
[X] Keep Malice as End Boss. Malice will continue to amass power and begin taking over the Eye/Maelstrom. Potential end-game alliance of all other factions against him. Potential for large outbreaks of Heartless across galaxy from Malice cults, which will act like a hybrid of Daemon Incursions and Ork attacks.