Who brought Relius back after the Dunamis gutted him?
It was Shulgi, pretending to be Relius, in the palace bedchambers, with a candlestick.
Does the Sleeper reside in our multiverse, and thus the Voices need to break through Ean, Sekh, Sheldon, etc. in order to wake it?
It sleeps where the Great Idea used to be. Technically outside the multiverse, I suppose. The Voices are sentient, subconscious extensions of the Dreamer's will. Everything is its dream, but
they are more so than most. Ean
et al. are guarding the path and will need to be disposed of before it can be awakened.
What happened to Adrahasis and Adrasteia? Are they part of the Voice-battling team along with Ean and co.?
Another Epilogue said:
“I’m done over here,” sighed Shulgi, incinerating his opponent’s remains. Adrahasis and Adrasteia dropped down from one of the many tunnels that connected the halls of the palace. “The incursion is clear on that end,” Adrahasis reported.
What was Earth's additional white moon all about? White whale egg?
Sphere corpse. Time moves funny in the void, so it's really old.
What exactly caused the white whales to invade our reality and fight Ean's armada? Someone playing with interdimensional physics like the cultists and Senya did?
They just happened to cross paths.
What happened to the Spheres?
The Masters destroyed them, and in doing so gained valuable data which they then used to create their Iae-hacking program.
So who was channelling Gilgamesh as the Dragon Emperor? You never confirmed Marduk, but I'd like to know if he survived the Void and how. Spheres were alive back then, right?
A combination of Marduk and Zeus and whatever else they ate. Spheres retroactively don't exist some time after Dio meets the Masters but I'm not sure how to express it, so yes, just assume they were. The Marduk-Zeus entity didn't stay in the void long, it tumbled out of another portal rather soon.
Any chances for that Imperial Culture loredump?
We'll see. I'm actually thinking of writing a short story set at the height of Shinari power (sometime during the ten years in between Dio's adventures and Ean's awakening) from another perspective. That setting was underused.
What happened to Ares once he entered the Olympus Rift? Did he father Adrahasis and Adrasteia? With whom?
Found his way to another planet. Met and fell in love with another immortal. Ruled the planet for a while. Had kids. Got eaten when the Dragon Emperor came knocking and conquered the planet.
Interestingly, it seems that Ares has turned out to be the most fertile of all the immortals.