I get asked a lot of questions on whether I base my characters on real people. It's a mix of what I observe in real life (how an actor looks in an action film etc) and what my artists interpret my characters to look like. I basically just give my artists a description of hair color, body build, outfits, etc. and they go from there. It's just depends on the interpretation. But the point is, they have to look badass.
There are some real-life people in the comic book. Myself, for instance, as the "author" character, and my friends and their band logos. My artists asked me what I wanted some of the characters from the script to look like (example, the background characters such as vampires who fight a main character etc) and I decided to have my friend's images in the comic book, for fun, so they get to be characters in a scene, and to help promote their bands too.