"But why would Sombra do that?" I pressed. "You said it yourself. The Crystal Empire had been fighting war after war against the Yeti Tribes due to their raids into the Empire's territory. And this had been going on since well before Sombra took power. And that Sombra continued those wars against them during his reign. Why would he take them with him, just so they could cause a headache for him again in the future? It's just not practical."