At the end of "Dune Messiah", Paul walks into the desert, a blind man, leaving his children in the care of the Fremen while their aunt Alia, Paul's sister, rules their empire as regent.
At the end of "Dune Messiah", Paul, a blind man, walks into the desert alone, in accordance with Fremen law. He leaves his children in the care of the Fremen while their aunt Alia, Paul's sister, marries the Duncan Idaho ghola and rules the empire as regent.