Concept

General Fantasy

Homebrew 5e

Working on the principle that The Universe is Old, no one remembers just how the world came to be. The Dwarves, first to emerge from the depths of the earth and conquer their neighbours, say it was brought to be when dragonfire from the First God scorched the great black waters and exposed the rich soil beneath it.

Dwarves conquered the monstrous Orcs and short-lived Humans and turned them into servants, sent Halflings to hide themselves away in the Feywilds, and bartered with the small pockets of Elves scattered across the continents - as they were unable to defeat their magics with numbers -, reigning for several long centuries. Eventually they grew complacent and the Orcs and Humans -with the help of the Elves and Dragonborn - turned against them, rising up to overthrow the vast empire and driving the remaining Dwarves into hiding deep within the mountain ranges they emerged from.

Orcs and Humans, free from the chains that held them for so long, spread across the continent in the wake of the collapse and rose into their own kingdoms. Halflings, no longer under threat from the Dwarves, began slowly moving their villages onto the Material Plane, though centuries of living with the capricious fae has left a mark on their society. Even stranger, odd people have been popping up, devilish traits sometimes overtaking whatever other features they have. There is still no shortage of hostility to the rare Dwarf that shows its face, however, but a tenuous peace has slowly crept over the land, broken only by small skirmishes and border disputes instead of all-out war.

Laws of physics are standard D&D 5e physics, with a strong leaning toward the Rule of Cool

Medieval based, though augmented with magic and other innovations

Tweaked 5e, where spells have a 2% chance of misfiring and causing a wild magic surge instead

Humans and Half-Orcs are the most common races, followed by Orcs, Dragonborn, Elves, Halflings, and finally Dwarves. Half-Elves, Tieflings, Genasi, and other races are extremely rare and are judged on a case-by-case basis.

(yeah its basically taking all the nice and shiny worldbuilding in Mordenkainen's and saying 'lol no')