"I guess we've got some time to talk, then." I said to Lartara. "I haven't gotten to read the history yet. You said the war happened due to overpopulation?"
"It was before the castes," Lartara nodded. "Supposedly Lycothans were somewhere between what Warriors and Alphas are like now. Strong and aggressive like us, but calculating and ambitious like them. They were also very long-lived. At least as long as the Alphas live now. The population got to be too much. Lycothans were very territorial, and conflict broke out over resources and land."
"And that destroyed the environment?" Eira asked.
"It escalated very quickly. They had the worst traits of all of us, with nothing to temper it. Great cities were built to house the growing population, but were left in ruins by the war. The only bit of the natural world on Lycothos that survived was the Last Grove."
"So the castes were...?" I asked.
"They were a solution to Lycothans' basic natures. They made the species have to depend on each other. Alphas have the ambition but not the strength to back it up or the aggression to make things personal. Warriors have the strength and aggression, but we're not looking for advantages over each other. We bond with our sisters. Servants don't have strength or ambition, so they keep the society stable."
"And thralls?" Eira chimed in.
"Thralls... came later," Lartara hedged. "After it was obvious that the castes alone wouldn't allow Old Lycothos to be rebuilt."
"When the colonies started," I reasoned.
"Yes. The ability to turn other species didn't start until Lycothans looked to other worlds to rebuild. They had the opposite problem. There were too many of them to live comfortably on Lycothos, but too few to pacify and restructure the worlds they found. At first there were no thralls, but the Alphas decided that just the Warriors taking a world was... inefficient."
"So they made it a virus," I said, connecting the dots.
"They discovered it by accident. It's actually a gene they first saw on one of the worlds. Some wouldn't turn normally. They'd become mindless. They discovered that with a virus they could trigger the Thrall Gene in a population before the warriors moved in, to prevent an organized response."
"And that's how they took Earth," I responded.
Lartara nodded. "Highest occurrence of the Thrall Gene in any colony to date. Exclusively on the Y chromosome. There are thralls out there that we haven't even found yet, just living feral."
"Just like that," I said, letting it sink in.
"Crazy when you think about it," Eira replied. "I guess they're happier out there, though."
"Maybe," I mumbled, not entirely convinced.