Mark Roper was a 24th century Human male. By the late 2350s, Roper was serving as head of the Federation embassy on Betazed.
In 2359, Lieutenant William T. Riker arrived on Betazed to serve as the Starfleet liason to the Embassy. By then, his daughter, Wendy, and assistant, Grace, had been with him on Betazed for about three years.
His wife having passed away a few years before and having no sex life of his own, Roper liked to constantly ask Riker about his possible romances so that he could get a vicarious thrill through him. He even bet Riker 200 credits that he would never become intimate with Deanna Troi. Eventually Riker did become intimate with Troi, but he told Roper that he hadn't and paid him the credits telling Roper that he had won the bet.
He liked to call Riker "Captain" since the general word in Starfleet was that Riker was on the fast track to command. Roper thought he would start calling him Captain now to beat the rush. (TNG novel: Imzadi)
Alternate timeline[]
In an alternate timeline created by the death of Deanna Troi in 2368, Roper died in approximately 2398. (TNG novel: Imzadi)