BEL RIOSE -- In his relatively short career; Riose earned the title of "The Last of the Imperials" and earned it well. A study of his campaigns reveals him to be the equal of Peurifoy in strategic ability and his superior perhaps in his ability to handle men. That he was born in the days of the decline of the Empire made it all but impossible for him to equal Peurifoy's record as a conqueror. Yet he had his chance when, the first of the Empire's generals to do so, he faced the Foundation squarely. (Foundation and Empire)...
Bel Riose was the last great general of the Galactic Empire, serving under Cleon II. He dreamed of glory and often expressed a negative opinion towards the Empire's cultural and technological decline.
Riose learns of the Foundation from Ducem Barr, a noble of the planet Siwenna. Correctly interpreting Barr's tales of "magicians" as the remnants of science in the Periphery, and witnessing some scientific advances made by the Foundation itself in the form of a personal force-shield, he decides to conquer the Foundation and utilize its scientific resources to revitalize the dying Empire. En route to the Foundation, he captures one of its Traders, Lathan Devers, and holds him hostage alongside Barr in an attempt to gain intelligence over the Foundation.
Although Devers and Barr escape Riose and make their way to Trantor in an attempt to gain an audience with the Emperor, the forces of history make their efforts meaningless. Fearing Riose's power, Cleon II orders him back to Trantor and has him executed for treason, as per Hari Seldon's prediction that by the end of the Empire, any military officer who was to gain enough power to threaten the Foundation would be prevented from causing harm by the central government's own fear of rebellion.