One day, Earth was struck by a meteor, and this meteor carried within it a strange substance that spread across the world and mutated the remnants of humanity. Magic was born and the landscape was changed forever. Technology shifted, taking advantage of the peculiarities of the arcane, and eventually history forgot the old world entirely.
This world is a world of magical machines, of wizards and demigods, where an arcane form of steampunk is simply the way things work the best in the absence of fossil fuels. It has been centuries since the world was changed, and many strange races of man arose. A handful of them carry a legacy of magic in their blood, allowing them to perform strange and wonderful feats simply as a matter of instinct. Magic that has twisted many to no longer appear human, in some cases, magic that has become so commonplace that those changed by it can no longer go without mana in their veins or risk a very painful death.
There are those that carry the truth of the old world with them, either ageless people from before the disaster who remain tight-lipped, or generations of strange emotionless scholars who keep the secrets of history locked up for fear of history becoming muddied.