Long time ago, the races learned how to use the <> to amplify magic, creating artifacts and other objects of wonder.
But there was a war, and the power of those amplified magics were incredible, tearing the world up, and the lust for power eventually led to the development of a method of using these <> to augment a caster’s personal power, changing them fundamentally into a being of magic – but also driving them irrevocably insane.
So in trying to end the war they shattered the world and all of their secrets were lost in the destruction.
Over time, the world has recovered, and some of the secrets re-discovered, including the creation of Arcana Golems.