These Vulcan crewmembers served aboard the Seleya in December 2152 when the ship was sent out to chart the thermobaric clouds in the Delphic Expanse. The following year the crew was discovered aboard the wrecked Vulcan D'kyr-type combat cruiser by the crew of Enterprise.
They were infected by the neurotoxic effects of the trellium and became insane. Their appearance changed due to several lesions and they talked no more. They also became violent and attacked the away team of Enterprise, Captain Jonathan Archer, Sub-Commander T'Pol, Lieutenant Malcolm Reed, and MACO Corporal F. Hawkins, with several metal bars used as weapons. They also destroyed the technology aboard the ship which allowed to communicate with other starships and flooded the auxiliary control room with hexafluorine gas after they disabled the controls of the bulkheads.
All of the crewmembers died when the Seleya was destroyed in 2153.
Several of the crewmembers appeared T'Pol in a nightmare she experienced a short time later aboard Enterprise. In this nightmare she was walking along a corridor and used a turbolift when she was attacked by one of the crewmembers. She escaped the turbolift and was attacked by several more of the infected crewmembers until she woke up due to the contact with Doctor Phlox in sickbay. (ENT: "Impulse")