Dorium Maldovar

Dorium Maldovar was a black marketeer in the 52nd century.

Biography
In 5149, After hearing that she was in search of time travel, Dorium met with River Song in the Maldovarium bar to offer her a Vortex manipulator that was, according to him, "Fresh off the wrist of a handsome Time Agent". As payment Song offered him a Callisto Pulse which could disarm Micro-explosives from up to 20 feet. When he enquired as to what kind of micro-explosives the pulse could disarm, she responded by saying the kind that she had just put in his wine. He was then forced to give her the Vortex Manipulator. (DW: The Pandorica Opens)

Dorium sold to a trio of Headless Monks with a Judoon's brain that contained a security protocol. As his customers left he questioned their motives for kidnapping "the child" and told them not to make the Doctor mad. (WC: Prequel (A Good Man Goes to War))

Dorium was one of many people who owed the Doctor a debt. He was summoned by the Doctor to help in the mission to rescue Amy and her baby at Demon's Run. He did not serve in a combat role but went into the station's computer and discovered the Melody Pond had 'Human plus Time Lord' DNA.

Dorium made a fatal mistake when he and the others were surrounded by the Headless Monks. He didn't believe they would harm him as they were his friends. He approached them with open arms. They swiftly killed and decapitated him. (DW: A Good Man Goes to War)

Behind the scenes

 * Dorium is given the additional name of Maldavar on Simon Fisher Becker's online CV.
 * It seems likely that this (possibly a different spelling of Maldovar) is a descriptive term for an entity from the planet Maldovarium, which Dorium could be. Further, shortly prior to his death, Dorium was referred to as "Mr. Maldavar" by the Sontaran, Strax.