Robert Singer was a human living in an alternate earth, where he was a producer of a television series called Supernatural, which narrated the life of Sam and Dean Winchester, but only as a narrative fiction. Sam and Dean encountered the series and its set and producers when Balthazar sent them into the alternate reality to keep Virgil, and by extension, the archangel Raphael, from taking hold of Heaven's Weapons.
He oversaw production and the filming of the show and was one of the first to notice the odd behaviors and actions of Sam and Dean, or, in his eyes, Jared Padalecki and Jensen Ackles, the actors playing the characters of the respective Winchester brothers. He thought the two were involved with illicit drugs, and raised this concern to the showrunner Sera Gamble. The two agreed to have the creator and original showrunner Eric Kripke intervene by talking to the brothers. Immediately after Kripke's arrival, however, Virgil arrived and killed most of the people in the set. Robert was the second to be gunned down by the angel, right after Kripke.