I think it's a good idea to remove less purposeful characters - for instance, Ms. Momoi and Nagatomo are edge cases. Yoshikuni is not, with devoted screen time and attempted character development.
So:
Amaimon +30
Arthur Auguste Angel +30
Astaroth +30
Behemoth +30 (You might as well put in "generic coal tar".)
Ernst Frederik Egin +30
Grigori +30 (This is a group of people. If I recall, the anime named them after the three Magi - Balthazar, Melchior, and Caspar.)
Igor Neuhaus +30
Izumo Kamiki +30
Konekomaru Miwa +30
Kuro +30
Mephisto Pheles +30
Michelle Neuhaus +30
Mike +30 (The foxes don't have enough personality in the anime to make a judgement call.)
Ms. Momoi +30 (She's a stock character with no purpose other than firing Rin. Again, not much information.)
Moorkin +30 (Again, stock demon.)
Nii-chan +30 (Niichan hasn't established a character.)
Noriko Paku +30
Reiji Shiratori +30
Renzō Shima +30
Rin Okumura +30
Ryūji Suguro +30
Satan +30
Shiemi Moriyama +30
Shirō Fujimoto +30
Shura Kirigakure +30
Takara +30
Uke +30
Ukobach +30 (Leaving Ukobach in because it did have a character so people can make calls on him.)
Yoshikuni XI +30
Yukio Okumura +30
Yuri Egin +30
I'm trying to avoid "who the hell is this guy?" reactions.