Explain what is Mokou doing: 打小人,Da Xiaoren is a Chinese culture that is intend to cursing those who is causing you trouble in everyday life. She is using a slipper to beating at a human shape paper. Similar to Japanese straw man nailing.
Or a Death Note. Now that I think about it, there are a LOT of anime revolving around serial killers named "Kira" trying to keep their identity secret with supernatural powers... And yes, two is a lot when the premise is that specific.