To me a "hunter" isn't someone trained from birth, with a membership to secret organizations and access to high-tech vampire-slaying nanobot swarms.
He/she works at the supermarket register or is trying to make ends meet as a second year college student when they see something they shouldn't have or survive an encounter with something insane... and they just can't go back to hiding. They just can't ignore it, they have to Do Something About It even if they fully realize they're way out of their league. They aren't respected by their peers - they're the person you end up seeing on the news raving about their neighbors, leaping over fences and being chased by the cops for doing something really illegal, stupid and suicidal... only they happen to be right.
Obviously there are many ways to do it! Whatever is fun to you, @Cobaltasaurus .