The Tyrant

The Tyrant is the term by which some, most notably the Bene Gesserit, knew Emperor Leto Atreides II.

The term is associated with Leto Atreides II because of the iron grip by which he ruled the known Dune universe for some 3,500 years, a period in which many ambitious groups, especially the Bene Gesserit, were prevented from wielding any significant power.