Let me reinterate, this is my interpretation of what I think something like "Dragon Conquer America" should have been. Here we have D&D dragons ad many other fantasy Creatures. I will discard the half world magic barrier, and will say simply that magic does not exist in what we know of as the Old World. The Old World consists of three continents, those would be Europe, Asia, and Africa, those continents exists just as our history up until 1492 says they should. There are no monsters, no magic, and no fantasy races other than humans. North America and South America as well as the Carribean is populated by elves at a similar technological level as those Native Americans they replace. There are also dwarves in New Zealand and halflings living as aborigines in Australia, Gnomes also dwell in the woodlands of New Zealand, while the Dwarves tend to live in the mountains.
Some of the regions where the nastier Native American Empires dwelled in our world are instead populated by Orcs, and they just love to make sacrifices of the elves to their god Gruumish. The Elves of North America live a less organized existence. There are different kinds of elves in different parts of the Americas, there are the familiar woodland and wild elves, there are also grey elves living in the mountain ranges, their are elves living on the plains and the deserts out west. Magic works in the Old World once it gets their, but the elves and other fantasy races did not know the Old World existed until it discovered them, and then things begin to change in both hemispheres. That is the scenario I am presenting here. There are also various aquatic races living in the Caribbean and through much of the Pacific Ocean These races tend to live in shallow water, they can transit through deep ocean areas, but the crushing depths of the deep ocean is not a place for them to live.
This is a D&D setting where the various continents are monoracial or biracial until the Age of Discovery begins. Christopher Columbus' voyage changes everything. There are three races of humans: Europeans, Africans, and Asians (also including Indians from the Indian subcontinent). That is the extend of the human world, history of these three continents has generally played out the way our history books say, No one there really knows how to use magic, no real monsters have been sited. The New World consists of three continents as well. North America, South America, and Australia and the Ocean in between Elves and Orcs inhabit North America. Elven races include High elves, wood elves, wild elves, gray elves, aquatic elves, and drow. the Orcs inhabit the surface and also live under ground along with other goblinoid races.
