This unnamed vampire was the leader of the Morest nest.
He was in charge of a nest of vampires residing in More Rest Hotel. He was first shown comforting a lone vampire named Kris who had recently lost her own nest thanks to a purge set out by the British Men of Letters. He fed her some blood and told her she was safe now.
Just then, the Alpha Vampire arrived. He told them he doubted their safety, but had useful information to give. He informed the nest of the location of the British Men of Letters compound, and everyone - except for Kris - set out to exact their revenge.
This vampire and his nest were able to kill a few operatives and surround the compound, surprising the ill-informed operatives and the two hunters present, with the exception of Pierce Moncrieff, who was secretly working for the Alpha. However, Sam Winchester demanded the capture of this one and he was dragged in to the conference room to be interrogated.
He was asked about the source of his knowledge, about how he knew where the compound was, and the vampire confessed that his father told him, stunning the operatives since they weren't expecting it. They originally believe the Alpha was elsewhere, and never thought he would relocate.
When the vampire mocked them for their seemingly inevitable death, Mary Winchester beheaded him in retaliation. To this vampire's misfortune, his entire nest was wiped out, as the British Men of Letters had intended, and his father the Alpha was also killed during the raid. Kris too, was not spared.