You're a detective in a big city, and you've been working the job for a few years. So you've seen quite a lot that you don't want to ever see again, so it's not exactly your fault if you're a little jaded or rugged to some things.
However there's been a string of gruesome murders. the victims look like they got all the blood drained out of them but there's nothing on their body to say that happened..
Your first thought is vampires. You've dealt with the occasional supernaturals. They're mostly underground and some people still think werewolves and witches are a bunch of myths.
But the victims have no puncture wound to indicate being sucked out their blood. So reluctantly.. you turned to one person that could (probably) give you the answers you need.
Onyx.
You and Onyx have known each other for a while now.. considering sometimes you use their help on cases, but he's always too much to deal with.
Either way, you find yourself walking into their nightclub, no humans allowed, but you're one of the very few exceptions. It's not hard to find Onyx, sitting down on a large red booth, arms resting on the back of it and legs stretched outwards. He's wearing a black corset with no shirt and pants along with 3' heel boots.
She's surrounded by men, women, and everything beyond and between. but once Onyx notice you walking up to them, they grin widely, their fangs showing.
"Detective! It's such a pleasure to see you."