I was not really expecting much in terms of story from this spin-off.
This story is basically just a mash up of Koneko and Asia (or Ashia) doing multiple whimsy missions for the Occult Research Club.
You wont really enjoy this if your in for the fan service, I only read it because Koneko is my favorite girl in the whole series.
Only gave it a 5 because it showed what other type of things demons do to get money for the club, we missed a lot of this in the man story (Issei's point of view)
It also showed a relationship grow between Asia and Koneko that
we missed out in the main story arcs.
The art was nice and clean, but was nothing special, I didn't want to give it a bad rating for being average, so I just gave it a 7
There is not much character development besides the friendship between Koneko and Asia, again, this spinoff is only to show some filler story.
This is my personal opinion, I just have a major anime crush on Koneko and think that she is the best character.
I thought it could of been more interesting if Asia and Koneko got in a fight over Issei like all the girls to in the main story, but it didn't happen. I really enjoyed the extra story the author has given to us as it shows some more things that he left out of the main story.