Mazao has a dark past, full of bloodshed and sin.
No matter if it's because she was just a child at the time, was unfortunately subject to wrong education, and driven by evil teachers and environment to act that way; or because the current her has already lost her past memories, making her different from her past self... Many would likely not see these as reasons to absolve her of her sins. Zhu Shi might be prone to making such a judgment, but this world is not so forgiving. I also believe a person cannot simply wash their hands of their past.
At the same time, I feel these are insignificant issues.
Because I am scum. If the same things happened to me, I wouldn't care. Thus, after hearing about Mazao's dark history, I simply feel my understanding of her has become richer. I have nothing more to think about beyond that.
I can still embrace Mazao without hesitation.
