Who is Summerset from Origin in Death and what is their importance?

Majordomo to Roarke, Summerset is a constant source of amusement for Dallas. She enjoys pushing his buttons by leaving her car parked in front of the house instead of putting it away, or hanging her jacket on the newel post when she comes home. Summerset has connections, and reveals that he knew Wilfred Icove during the wars. Summerset met and worked for him in London forty years earlier.