Well, it appears that Chaos unites everyone. After beating the Vampires back to Castle Drakenhof, the Warriors of Chaos emerged in force and started their apocalyptic march down south. As I ended my turn, I was greeted with multiple pledges of alliances from the remaining Empire and Bretonnia factions, as well as some Dwarfs. I accepted them with haste, and then made peace with the Vampires (as well as Jewing 3000 coins from their treasury to accept the peace offer) so I could focus on driving back the Chaos threat.
Ostermark, who declared themselves an independent kingdom several turns before, came before me to join my Empire, which I gladly accepted, taking in their lands and armies. But I discovered I had to move fast, as Varg was closing in on the former Ostermark holdings. I quickly moved Karl Franz north to meet with the former ruler of Ostermark, and together we drove back the Varg tribe and seized a couple of their holdings, while I move another force up to meet with them. Only time will tell if he will meet with them however, because several Skaeling armies are creeping their way towards the Emperor...
I haven't been this excited about a Total War campaign in the longest time.
Oh, guess I should finish up here.
So I ended up driving the Chaos factions to ruin, since Varg and the Skaelings kept throwing themselves at me with shitty tier 1 Chaos units and ended up getting completely manhandled. I managed to take over Kislev after purposefully letting them go extinct against Chaos (seriously they are THE hardest faction to get an alliance with) and beat back the waves of Chaos before they could venture too far south.
Eventually Archaeon himself and Kholek marched towards Kislev, where Karl Franz and three high-ranking generals were recouping their losses from previous battles. Upon seeing the Everchosen emerge, Balthazar Galt marched his Imperial forces towards Kislev to aid his Emperor. He made it just in time, and the combined forces of the Empire wiped out the forces of Chaos. They had no home to retreat to either as two Empire Lords burned the Chaos North to the fucking ground.
As time went on, with no more foes of Chaos to destroy, Karl Franz campaigned and conquered all of Bretonnia and brought the Southern Realms to heel while exterminating the filthy Greenskins. With the Empire and the Dwarfs (who resided completely on the Eastern side of the map) being the only powers left standing, I declared the campaign a victory and quit.
Total War: Warhammer Megathread - Psy get a fucking PC edition