Joseph the Monster Killer
Joseph is getting too old to keep up his duties of keeping the kingdom free of evil creatures. He's not quite ready to retire but he will gladly pay you to do the job for him.
Talk to him in Haven, just west of the travel gate, and he will give you a contract that details which monster and how many must be killed. You can cash in the contract anywhere once it is filled. His workload is pretty steady - he gets new contracts every 20 minutes or so.
Crafters can now craft a book, the Hunter BOD Book, that will store the contracts. You can fill and cash out the contracts without having to remove them from the book.
Loot what you wish from the corpses before adding them to the contract!