Who is Emperor Cleon I from Forward the Foundation and what is their importance?

Emperor Cleon I is the last Galactic Emperor of the Entun dynasty, Cleon is born the same year as Hari Seldon, whose psychohistory he patronizes for decades, expecting practical results. Cleon is frustrated by how little he gets. Cleon detests the trappings of office and it is rumored that Eto Demerzel, first Cleon's chief of staff and later First Minister, is the power behind the throne. When it is rumored that he is a robot, Eto resigns and disappears, having suggested that Cleon name Hari as his successor. Hari struggles in the thankless job for a decade until during an attempt on Hari's life, Cleon falls victim to a deranged palace gardener. A military junta rules for years before an even less competent distant relative, Agis XIV, assumes the throne.