Classifications of Adventurers;

For Hire: Can be career or simply part time adventurers. They will often do smaller jobs for a bounty. Capability range is large. 

Monster Slayer: Career adventurers. Target and wipe out high grade monsters, and can even be employed to slay demons for an increased fee. If they specialize in Demon Slaying they will sometimes be called "Demon Slayer"

Rogue: Wanderers that make most of their gains from finding guarded treasures or selling high quality monster parts. Can be very dangerous, and have low scruples.

"Holy": Feel that this is their calling. Say they are in contact with Angels. Capability range is large, but usually high. High mortality rate.

Relic: A career adventurer that has access to high quality artifacts or relics and knows how to utilize them effectively. These adventurers are the most capable and will be paid handsomely to deal with monsters and demons. Rare but enduring.

-The Adventurers Guide to the Continent