“War now to prevent war later?”

“Not to prevent, Caesar. To soften. We no longer even vaccinate against the plagues which claimed the billions of the last war, but samples survive. Imagine if they were loosed on Mars, the new world uninhabitable for a century. Or imagine if they were let loose on Earth by those on Mars, fearing their own destruction. What if some new technology we’ve never tapped for war, Mitsubishi cloth or smelltracks, turns out to be able to wipe out a planet in a day? We need to find that out now, in a gentler war, one where no one is willing yet to go all the way. That was Apollo’s project. They designed their special coat, the weapons inside, trained, wrote up plans for how the war would probably begin, how to proceed. Later the Mardis chose to join them, but Apollo would have done it on their own.”

As a storm’s first tremors in the still-sleeping deep shake a slim ship, not yet in danger but helpless against the tempest that must come, so Caesar’s trembling shook me. “Apollo’s coat showed ruins, soldiers, even myself uniformed for war.”

I glanced back briefly at the Emperor’s guards, his childhood ba’sibs for the most part, or Guildbreakers, reliable as caryatids in the face of secrets, dumb as stone.

“Yes, Caesar,” I answered. “Apollo’s coat is a simulation, this world one year into Apollo’s predicted war. The people who don’t appear in it, the ones it makes invisible, those are people Apollo thought would not survive the first twelve months.”

“Including themself,” he supplied.

I nodded. “Apollo would have died on the front lines. It’s not a fate they wanted, but it’s what they expected, and when we faced one another in battle—”

“What you did wasn’t a battle, Mycroft,” he interrupted, grim. “It was a murder.”

“It was to save Earth and Mars together, Caesar! My attempt to let us vent our war rage without killing millions. I had to stop the Mardis, but if I could make people as outraged as a war would have, get Earth to vent its killing rage on me, instead of billions on billions, maybe it could’ve been a tiny war, we two, Saladin and I, against the Mardi nineteen, ending with all humanity, ten billion together, killing me. Apollo understood. Our battle might have been enough!”

“Not battle. Murder.”

Something in me dared glare back at him. “What is a battle if not a confrontation between two enemies, armed and prepared to kill or perish in a struggle whose outcome will determine the fates of many? It was a battle, Caesar! Saladin and I against Seine and Apollo. We were soldiers. The first soldiers in three hundred years! The other Mardis’ deaths, those I admit were murders, but Apollo was a battle, the first and only battle of Apollo’s aborted war.”

He choked. “Second.”

“Caesar?”

“It was the second battle.” He released me, turning to peer up through the alley toward the Capitoline Hill behind us, its columns bright as a lighthouse through the rain. “You think you shed first blood in this, monster? You were years too late.”