Divinity: Pursuit of Freedom

In an medieval-esque world, magic reigns supreme. With most people having something called "Mana" in them. In the kingdom of Altriche however, Mana seems to be absent, upon an attack of mysterious invaders, one of the Kingdom's Elite Guards rises up, and takes two kids under his wing, these kids, have the Gift of Mana, which is considerably rare for a kingdom where there is none.