Duality (Riven Worlds Book Six). Amaranthe, #19

**The explosive conclusion to the epic Riven Worlds series** Humanity was granted their time to prepare. Now that it has come to an end, all Miriam Solovy wants is one more day. The Rasu civil war engineered by Alex Solovy and Nika Kirumase has provided Concord the time it desperately needed. Every weapon, every technology, every tactic will be brought to bear in a bid to defend thousands of worlds and trillions of people from annihilation. The enemy that emerges from the civil war victorious is like nothing Concord has ever faced.
A boundless legion of Rasu-now interlinked and of one collective mind due to their integration of kyoseil-prepares to sweep across Concord space in a devastating tidal wave. But there might be a way to stop them. It will mean two individuals must take upon themselves the burden of committing genocide, so the innocent beings they protect need never know how such an act comes with a price. "There has never been a timeline like this one before."A war has been waged for endless aeons.
Our greatest champions fight it again and again across millions of years, in a tireless endeavor to save not merely innumerable lives but existence itself. With Mesme's secret revealed, the enormity of the stakes is clear to all, and humanity and its allies are united as they brace for the return of the Rasu. But the enemy has a secret, too-one that may ensure Concord's destruction, as it has countless times before.*In Amaranthe, where exotic alien life, AIs, wormholes, indestructible starships and the promise of immortality rule the day, no feat seems out of reach for humanity.
But when the worlds of Aurora Rhapsody and Asterion Noir collide and the Rasu horde descends upon them both, more will be asked of heroes past and future. More will be given and more taken, and when the dust settles the very fabric of Amaranthe will be altered forever.