Dorium Maldovar

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

Biography
In 5145, 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 "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 twenty 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 forced to give her the Vortex Manipulator. (DW: The Pandorica Opens)

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

Dorium was one of many people who owed the Doctor a debt and was summoned by him to help rescue Amy and her baby at Demons Run. He did not serve in a combat role, but went into the station's computer and discovered that 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 believed they were his friends and would not harm him. He approached them with open arms, but they swiftly decapitated Dorium and added him to their ranks. His headless body was subsequently killed by the Doctor's remaining allies. (DW: A Good Man Goes to War)

The Doctor was told by Gantok (a Viking he had just played a game of Live Chess against) that Dorium had information about the The Silence. In the Cave of Skulls they came across a box inside it was the decapitated head of Dorium. Dorium then told the Doctor that on the fields of Trenzalore, at the fall of the Eleventh a question would be asked, a question that must never be answered and would the Doctor want to hear it..

He then procceded to tell the Doctor the question but instead the Doctor then took him aboard the TARDIS. Dorium told the Doctor that he must die at some point the Doctor told him about being in a time machine and that he could keep running until he got a call from a Nursing Home which told him  that his friend  Brigadier Lethbridge-Stewart  had passed away in his sleep and saud how he kept talking about him. The Doctor then decided to go to his death.

Later on a Headless Monk was seen walking with Dorium's head back to the Cave of Skulls. The Headless Monk was then revealed to be the Doctor-having escaped his fate. Dorium asked how he had done it, The Doctor told him how and that he would now keep a low profile so the Universe would think he had died. Dorium then told the Doctor that Trenzalore and the Fall of the Eleventh are still waiting for him and the question which he revealed is "Doctor Who?" (DW: The Wedding of River Song)