Back From The Ruins: Try to save all and you will save none

It all happened so quickly, I was on the brink of promotion, and then the plague arrived, the kingdom fell quickly, as I saw the infected creatures enter the kingdom, I rushed to save my family, but they were already dead, ripped and torn to shreds, after that the kingdom fell, I took refugee in a village, Decades of training later I was giiven a simple task, go to the kingdom of Ty'er originator of the plague