" This is how we fought the Causality War. A war where you never saw soldiers from the other side, not because you were launching high tech projectiles at each other from ridiculous distances, but because you almost never occupied a common frame of reference. The weapons you launched at each other were cascading chains of historical events, and each one simultaneously hit and caused colossal collateral damage, and did no damage at all, because what was left in its wake was a happy smiling world with no idea there was a war on. "

― Adrian Tchaikovsky , One Day All This Will Be Yours