UberBread
You could say that, she was, in a way, somewhat of a professional delinquent. Born of no higher nobility than high-class merchants, whose wares were multifarious and quite often, illegal, she became entrusted with deliveries and transactions of the most forbidden and cursed sort.
Lo and behold, her skills as a trustworthy and reliable merchant, able to successfully deliver her merchandise(or someone else's) in perfect condition and in reasonable time span, caught the eyes of unnamed supernaturals who required her dutiful service.
Of course, her clients weren't just reserved for the upper-class demons, angels, or humans. As long as they offered a reasonable price, she was willing to get the job done. She even gets contacted by multiple humans, for the requests of the retrieval and delivery of peculiar cursed items.
Indeed, she is an odd fellow, being a human who deals in the blackmarket often and makes moneymaking deals with supernaturals that one would not dare meddle in.
She soon becomes involved in the case of the item, Grimoire, and is thus given the job to retrieve it, and find a new resting place for it. A huge undertaking which, if successful, can prove not only boost her reputation, but also create a name for herself.
Yes, she is indeed determined to overcome whatever may befall her.
Oh, you don't know by now who I'm talking about?
Well, of course I'll tell you. Her name is-
Soriano Midorikawa.
Hmm, I wonder how she will do. What do you think?