The Curator nodded, "There would always be ponies that hate each other somewhere, but with the tribes working together it was negligible. That didn't mean it wasn't impossible that things could go wrong again, so I wanted a little insurance against that possibility, just in case. I was also going to be smarter about it this time, and leave the Gift of Life well out of it, as it had only caused trouble in my hooves. I designed the Crystal Empire, and created the Crystal Heart, then approached the crystal ponies with an offer of giving them a safe place to live from the frozen north in exchange for a small favour."