QUOTE (SoraZ @ 7 Aug 2016, 10:36)
Waaaghhh Ghazghkull will be successful (because anything else would just make no sense at all, even considering the adamantium-coated Plot Armor of the Imperium). Tyranids will eat large swathes of the galaxy. The Silent King will return and unite the Necrons. The last Eldar will die, which will bring the Eldar God of Death back, who will then kick Chaos' ass, but not before Failbaddon did something stupid again. The Tau Empire will fracture and turn into meaninglessness. The Imperium will also fracture, with a new form of Civil War coming.
Those are my thoughts to keep things interesting while advancing stuff a bit.
On top of that, I want to see something like Necron vessels beginning to enter the Sol System, being attracted by the awakening of the Void Dragon on Mars, who the machine priests think is the Omnissiah.
Half of the Adeptus Mechanicus is divided between either worshiping the God-Emperor or the Void Dragon. The ones who pledge allegiance to the Necron God combine the Imperial and xeno tech they have with what they have learned from the Dragon, transforming into what could be described as "next generation Necrons".
Mars is beginning to transform into a Tomb World. The Fabricator General realizes whats going on and cuts all communications with Mars from Terra and the rest of the Imperium when they begin broadcasting strange messages on the vox frequencies. The Custodes, for the first time in 10 thousand years, have been ordered to go to Mars to stop this threat before it gets worse. This leads to a second Civil War in the Imperium, on the same tier as the Horus Heresy, if not worse.