12 parts Ongoing Katherine, a goetian demon that had been making money on Earth through criminal activity, decides to get a job at I.M.P. to better support the family she has made with her boyfriend. A few nights before, Caliste had disappeared without a trace, and everyone was worried sick by the time Katherine stepped in.
Blitzo decides to instead make Katherine a replacement employee, or, in his own words, a stand-in. So, in short, Katherine gets the job temporarily. She gets to work for I.M.P. until Caliste is found. But as the days go by, she starts to really bond with her co-workers, to the point even Blitz is starting to see her as a real employee.
By the time Caliste does returns, the goetia has some mixed feelings, and it's because Blitz, like he did multiple times in the past, fucked up. Because of this, Katherine tries to heal the bond and trust the two had....along with helping with some other things.