The thing I love about a villain like a Night Ripper is that you only have to worry about them at night. I know it feels that way with a lot of villains, but plenty of murders and sacrifices happen during the day. A Night Ripper isn't going to kill people during the day. That's the Day Ripper's job. There's a very strict code among Rippers not to step on each other's territory.
What does Night Ripper do during the day then? I bet the Night Ripper in this movie is a really nice guy during the day. He goes to volunteer at schools. He works with the elderly, but once it's night, he gets ripping. He'll rip all night. Then the sun rises and he brings coffee and donuts to the homeless. People have different levels to them, you know?