so Adventurers like Bennett are kind of like officially sanctioned mercenaries. They're all contracted with their local branch of the Adventurer's Guild, where they get hired to take on Commissions, which can range from simple things like "go kill these monsters" and "help me deliver this thing" to more dangerous ones like "go kill this really big monster" and "please explore this new domain we found it seems dangerous", all in exchange for pay. It's a full-time job, complete with official uniforms. In their downtime, adventurers will go exploring to distant corners of the land in pursuit of treasure and fame.

So basically they're RPG characters except it's their real job.