@CookieMonster
Let me correct my writing a bit.
In normal circumstands, Maou should be, at least, annoyed or have a fear for what happened to her. Magical girl is a person who broke her into pieces after all. But, after she know about it, She is just okay with living with her killer.
It's not like she react this way, because she understand situation. But, she doesn't care about being destroyed in the first place.
I figured she might still lose her memories. So, she doesn't treat it as her situation yet. But, as this chapter showed, it looks like she knows and even protect her killer from that white mist, who might be another part of her. It's like she have been protecting her even since.
It's an odd situation going on here.