Second Foundation
As the Mule comes closer to finding it, the mysterious Second Foundation comes briefly out of hiding to face the threat directly. It consists of the descendants of Seldon's psychohistorians. While the first Foundation has developed the physical sciences, the Second Foundation has been developing Seldon's mathematics and the Seldon Plan, along with their own use of mental sciences. The Second Foundation ultimately wears down the Mule, who returns to rule over his kingdom peacefully for the rest of his life, without any further thought of conquering the Second Foundation.