This is certainly one twisted series on par with the likes of Elfen Lied and Hellsing. I'm hoooked
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Spoiler for chapter 21:
Possible the most epic moment was when Nagi kept a psycho monk in the path of a super powerful blast and said, "I'm your guide to Hell!"
EDIT: It makes more sense in the context.
Now waiting for chapter 22, which the raw came out a week ago.