Watch Nightwalker, it started out a 4 episodes long OVA, but a TV producer liked what he saw enough to turn it into a 13 episodes long show so they used the first 4 episodes originally produced to be OVAs as the show's first arc and then produced 9 more episodes with a TV budget so the show would be 13 episodes long, I'm just saying this because while the show takes a HUGE fall in terms of quality after episode 4 they didn't tone down any of the blood and nudity the OVAs had surprisingly enough so the episodes produced for TV still have gore and tits