Who wins the Long Game?
Of all the long lived beings and entities in the 40k-verse, which in your opinion has the greatest chance of emerging as the most successful? Not necessarily the sole survivor of them all, but the most likely to achieve lasting dominance?
A: The c'tan. Over however long it takes, perhaps the shards manage to gradually rejoin themselves, be it by chance, engineering or carelessness on the part of their captors. Perhaps some trancendent shards become aware enough of their past to truly become what they once were, maybe a few manage to emerge and topple their former masters in vengeance. From here they could do pretty much anything, imposing their rule upon the younger races of the galaxy and reigniting the War with the Warp fed deities and worshipers just like the days of old where time was to their advantage.
B: The necrons. Through whatever you may call it, conquest or conviction, perhaps a visionary necron lord such as Anrakyr, Imotekh or Szarekh manages to pull the divided necron empire back together in time to reclaim the galaxy from the threats within and without. The tyranids are driven back and/or defeated, the influence of Chaos brought back under control and the younger races either stamped out or brought into compliance, serving whatever useful end their masters may dictate. The hold on the c'tan is maintained and with stability achieved greater measures are developed to keep them contained.
C: The Tyranids. With too little too late amassed to stop them, the constant influx of tyranid Hive Fleets proves too much for the denizens of the galaxy to handle and their feeding frenzy drives all other life in the galaxy to extinction. The turbulence in the warp from so much resounding death may slow them for a time, but in the end they are stronger and more numerous for having fed on such powerful genetic samples, spelling even swifter doom for whichever galaxy falls under their ever hungry gaze next.
D: Chaos. With ever greater numbers of mortals succumbing to their divine influence and their power reaching near unstoppable levels, the very moment of the Emperor's death spells not only doom for the Imperium, but for every other being in the galaxy as Humanity falls completely under the sway of the Dark Gods. Powered by the four winds, an army of unstoppable fanatics and slaves marches forth, feeding the Eye of Terror's growth until the entire galaxy is naught but the gods' playground.
E: The Mortal Races. While no single regime will endure forever, the deaths of those now feeds the courage of those in the future, inspiring the next generations to continue the fight. One by one the enemies of all living things are brought crashing down, the tyranids eradicated, the c'tan and their masters brought to heel and the influence of Chaos stemmed and bled dry by enlightenment and understanding. Though the Imperium may not have survived, and the tau and eldar races lie bloodied or broken, Life itself continues to endure, refusing to submit to even the darkest forces the universe can bring to bear.
Stirring speeches aside, which of those do you perceive to be the most realistic outcome of the current setting?
Nonsense is our Salvation