Monster Slayer
Either out of heroism, vanity, masochism, or some other fourth thing or combination, you have decided to lift the curse of this land. The curse?
All monsters are blessed with near-immortality, strength and speed beyond any human,and a body the gods themselves would worship.
Thankfully, this isn't as bad in practice as it is on paper, everything in the universe has an equal reaction, every prize an equal price, and theirs?
They require so much more energy to function, and man since the dawn of time has survived by having stamina far beyond any other animal (except birds, but fuck those guys).
Rather than fight monsters, or run away from them, people are advised to go along with them, sate their demands until they pass out, and it's easy enough some of the time...
Monsters however, do have a way to compensate this...seed. The seed of a man contains magic able to sustain a monster for days, meaning, if a man succumbs just once...he is at their mercy forever.
And if there's several?
Oh dear...
Several weeks of endurance training, several hundreds of dollars (or pounds, whatever) of paranoid prepper purchases, and the refusal of chopping your cock off to hard counter these things later (that would hurt!), you set out on your journey...without really knowing what you're doing or how you're going to deal with this curse.
And very quickly, you had gotten yourself into a mess...