Machette lived in the <forgot the name> Empire, where basically might is justice (that's why she is a strong warrior), I think she was a warrior from a nation that lost to said empire, thus she was essentially a prisoner to be "used" by the winners.
At some point, she got pregnant from some random soldier. Then the Emperor, who likes strong women to make strong children, wanted a new woman, and a vassal offered Machette to him, and he liked her. However, after their first night, he considered killing the 1st child, can't remember the exact reason though.
That night, Machette took her daughter and escaped against all odds, fighting to the end until she was out of the empire, and started living in a small village. She later found out she was pregnant again, knowing who the father is, but she never told him.
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He goes on a journey with another biological sister (there are many sisters and brothers being revealed now), one with the rare job Valkyria, who acts as his guide in the empire.