Full of Dragons, Wyverns, and Humans, complete with racial prejudices!
Dragons have innate magical abilities, pure Humans have no magical capabilities from birth, meaning that magic requires great amounts of study.
Two forms of magic, Bending and Animus. Bending controls the 4 elements and their permutations (Earth, Fire, Water, Air, etc.), and can be taught/learned through intense study. Having draconic parentage or some magic artifact would help immensely. Animus magic is more common among Humans, and it follows standard schools of magic (evocation, enchantment, abjuration, divination, conjuration, necromancy, illusion, transmutation). Humans have an easier time learning it, and having non-humanoid parentage will still help. You can have one or the other, but never both. After a purge many thousands of years ago, almost no one human or dragon has magic save for a select few.
Physics works like it does in the real world, except people can lift far heavier objects than in the real-world (People who train enough can have a common max bench of 400 lbs). They can also take more punishment than usual, but they're nowhere near invincible. Armor keeps getting tougher and weapons keep getting stronger (and bigger).
Technology level of Monster Hunter/more advanced D&D Homebrew (Bowguns, sandships, actual ships, trains, planes, and automobiles on par with post-WWI). Most of that technology is found within human settlements and empires, with more advanced technology being found closer and closer towards the capital of the Empire of Prominence, Mordaria.
Two major events so far:
Magical Purge (name pending): Nearly all magic users in the entire world were wiped outing a collaborative effort between a man and a dragon that found a magical artifact that was designed to destroy all magic from a person down to the genetic code that made them predisposed to having it. Using the artifact and a whole cabal of anti-magical racists, they took over the human kingdom, destroyed all forms of learning dedicated to magic, and killed every magic user in a near-worldwide massacre. Thus, that person became the progenitor of the Empire of Prominence and the dragon who used the artifact became the first Wyvern.
The Great Wyvern War: The humans began hunting wyverns because they were easier to kill than dragons and didn't have any sort of pesky political structure that got in the way. wyverns were seen more as animals than as actual "people," so humans used wyvern materials to advance their own technology to the point where overhunting was common. At some point, the wyverns rallied behind a single, unknown leader and began regularly attacking human settlements. Humans and wyverns began fighting, and then both parties started minor skirmishes with dragons. The story revolves around Yamatsukami, a half-dragon half-human man, finding out about this and realizing that a war between all three factions might end up destroying the world, and so he sets off to try and stop it. He has no idea how he plans on doing this, but he'll at least give it the old college try, right?