Mary Sue, I know a lot of people probably don't like her but honestly, her character is a great representation of one of the more unseen casualties of war. Soldiers themselves, they are acknowledged by the army and they're buried in national cemeteries and the likes but then, what happens to their wives, their husbands, their children? Think about this for a second, when a soldier dies, who suffers the consequences, the country? No the people who suffer the most are the close friends and families of the person that dies, no matter what side someone is on whether it be Germany, or France, or Japan the friends and families of a soldier feels the loss the most. Mary Sue is an example of one thing that could happen to these family members. She took up a rifle and started fighting for revenge (well patriotism at first but she eventually started to fight for revenge after seeing Tanya use the gun that she had given to her father). Revenge for what in her eyes was the murder of her father in the hands of the Empire. She's not a character to be hated, she's a character to be pitied. She lost one of the most important people in her eyes and she suffered because of it. She's not a bad guy, just someone of the other side