Song Mingi was the only son and the youngest of his family, having 4 sisters. His father wanted a son that he could be proud of, and they kept trying until they had one. Mingi's family was poor and didn't have much to offer any potential male suitors for their daughters, so the oldest two married into families equal of their status. 
When mingi turned seven a war broke out in the country, and at such a young and tender age, with is father being to old to fight, he was taken in his stead. He was trained how to battle horseback for a couple of years before being put into battle, in the meantime he helped heal wounds of the soldiers who were fighting in the war. It wasn't long before he was fighting in the military long term, anytime they needed him he was fighting alongside the calvary, and is one of the best dragoons in the calvary he fights in.