6. Different races have different innate magical auras. If a human touches an Elf, or is affected by an Elf's spell, the next spell the human casts is disrupted. Elves and gnomes share friendly auras, humans and orcs have friendly auras, and there are no dwarves or halflings. Half Elves have the worst of both worlds; if they touch anyone but another half Elf, their magic goes awry. This leads to isolationist cultures, and very strange interaction between races. Different monsters have their own auras too, making some dangerous to even go near. A Dragon's aura is powerful enough to cause Elves and Gnomes to go mad, while demons and celestials have the same effects on humans and Orcs.
7. All monsters were created by wizards. Anything that isn't on earth is magically created by biomancers. Most were made for defending lairs, as pets, or as soldiers in armies; but over centuries, some escaped into the wild and bred. The most famous biomancers had signatures, so all the avian creatures created by the mage Longinus can be mind-controlled if you know the right spell. Many mages seek to find these ancient monster controlling magicks.
8. Adventurers are sponsored by nobles and aristocracy, much as artists were sponsored by patrons on Earth during the Renaissance. Adventurers are expected to deliver regularly, and are always well-equipped. The most famous and successful ones get courted by numerous nobles, hoping to increase their status by associating with great heroes.
9. Centuries ago, a tyrannical dictator killed all disloyal mages, hoping to cement his position as ruler. Now, only a handful of remote villages have mages, and they are fairly primitive. Magic can still be found and studied, but the old Inquisitorial Order still seeks out and kills magic-users.
10. In an ancient war, the humans defeated the Elves and fey, and a treaty was made, splitting the world into two parts. Each group keeps to its own side, and after more than a thousand years, tales of the old fey races are mere myths among humans. But the humans discover the existence of the other world, and plan to invade it, breaking the ancient treaty.