The Mana Dynamo is a sort of mega power plant.
It absorbs Mana from inside the planet and releases it in a form that civilization uses to power nearly everything.
It is an intrinsically wasteful means of generating power, and slowly drains the lifeblood of the planet.
It was created by the second civilization as a way to provide enough power for the entire planet using a single device
By harnessing the power of the Dynamo, the second civilization creates all kinds of technology that seems almost like magic.