TL;DR: Captain America Needs To Die

[Rory Wildwards]

Hail Hydra.

[CoffeeGrunt]

I once read a wonderful fanfiction where somebody killed the Emperor, and explored the havoc that would result. (Unfortunately it was never finished.) And the best thing about it was that things shook out in a way where you could have a Warhammer 50k in that universe; some characters were killed permanently, but that's okay, and they had a wonderful send off - Eisenhorn was a wonderful and terrible and fitting end, that was a mixture of 'you magnificent *******' and 'you utter idiot fighting Chaos like that' - yet the broad factions were intact. Some new, some melded together, but none completely squatted. Just on different sides, for plausible reasons.

The Shape of the Nightmare to Come? If it's that one, I quite liked it. Was interesting to see the Imperium fracture into a thousand "New Imperiums" of various breeds. Abaddon takes over the Cadia region but doesn't get much further because of the rest of the galaxy brewing up into the mother of all sh*tstorms. The Tau become utterly genocidal over time after seeing world-after-devastated-world ruined due to the Imperium's new civil war, turning them bitter like the Imperium was.

It also had a pretty great sequence of the last stand on Titan after the Emperor dies and the Warp tunnel under his throne opens, pulling Terra into the Warp and shattering the Imperial Fleet. IIRC, Mars falls to a tide of daemons afterwards, and Titan was the last stronghold in the Sol system.

The Emperor as a Chaos God was also interesting, and kinda made sense given that he'd been prayed to with the screaming wails of the dying, the begging of the destitute, and had been fed tortured psykers for millennia. The human within had gone utterly mad and evaporated, leaving only a pained being of human anguish.

Also seeing how various characters reacted to it all was cool. Such as Yarrick becoming a ruthless dictator who was eventually shot by his own men. The best part was that it made everything go to crap, but also laid enough hints of hope down that there was a chance for humanity to survive and prosper again.

[Morgrim]

No, this one was called 'Death of the Emperor' and featured several splintered factions of the Imperium that were (mostly) still allied, in the sense that other humans were better than the xenos, but more of a cold war situation since everyone else leapt on the chance to attack. Abbadon was delayed by every chaos god having a different idea of how to take advantage of the situation. Slaanesh was the most successful and got a minion into a position of High Lord of Terra, nearly causing another great religious Schism in the process that led to a massive civil war ripping through the Sol System.

Following is major spoilers:

Due to someone's brilliant but stupid move during the battle a major Nurgle incursion occurred on Terra during the fight (the portal was within the Palace, making it rather hard to close), which did very effectively stop the civil war as they took out the leaders of one side and then all the humans decided they'd better reunite if they didn't want to die. Everyone was very hard pressed to survive until they got a sudden unexpected backup... from Magnus and a large force of Thousand Sons. Considering the human armies were being led by the Grey Knights, much awkwardness occurred. Especially when someone pointed out it was their respective similarities that meant the two groups were fighting together really well.

Unfortunately it stopped soon after that point because the author of the fanfic became a published author and was understandably focusing on the stuff they could sell.

[CoffeeGrunt]

Ah, shame. Might check it out if it's decent.