A combat wombat. A disgusting character . Rescuing the princess or restoring harmony to the galaxy are only inconvenient annoyances on the road to your real objective of acquiring wealth and experience points. You want bragging rights . It even comes with a small sampling of the mega-powerful creatures on other planes, for when your characters get powerful enough to obliterate a roomful of oversized psychic vampire dragons in three seconds flat.
Characters begin at quite competent power levels, and progress is rapid.
Little attention has been paid to making the game world into a rich, cohesive setting. I suppose you, as the GM, could go to the trouble of contriving a complicated setting and peopling your adventure with deep and interesting NPCs, but they'll probably get killed the instant they meet the player-characters anyway, so I would suggest you save yourself the heartache right now and just concentrate on picking monsters of the appropriate toughness. I have attempted to answer such deep and probing questions by providing a short list of modern and futuristic weapons and vehicles. Pretend that there was a rip in the spacetime continuum which allowed future technology to fall into medieval hands. Or that the game really takes place in the distant future after the fall of civilization and trolls are really mutants.