Complex sentence: He takes her as his servant; she later becomes fiercely devoted to and protective of Paul's young sister Alia, and seeks to explain the girl's unique nature to the superstitious and wary Fremen.
Split into simpler sentences: He takes her as his servant; she later becomes fiercely devoted to and protective of Paul's young sister Alia. Harah then seeks to explain Alia's unique nature to the superstitious and wary Fremen.