Dr. Gabriel Valack was a prisoner inside a reinforced "bullet-resistant polycarbonate" cell at Eichen House until he escaped and took over the facility. His attempt to enhance Lydia Martin's Banshee abilities, which backfired and apparently killed him when Lydia's scream shattered his skull.
Dr. Valack was portrayed by actor Steven Brand.
He was once Chief Medical Officer at Eichen House. He performed trepanation on supernatural creatures and on at least one Banshee to amplify their abilities. The process worked initially but the increase in power eventually killed them all.
Valack had, via trepanning, a hole in the center of his own skull. In early appearances a functioning eye was visible inside this hole until the Dread Doctors removed it.
Most of Season 5 is a series of flashbacks revealed during an interview between Valack and Lydia Martin as he struggles to help her remember what happened leading up to a final confrontation between her friends and the The Dread Doctors.
Valack had the, so far unexplained, ability to appear as other people. He appeared as Conrad Fenris when picking up Lydia from the hospital and seemed to mimic Aiden's appearance while questioning her.
At some point, prior to his incarceration, Valack wrote a book entitled The Dread Doctors. It details the activities of a group of scientists who meld science with the supernatural. Valack used the pen name T.R. McCammon to protect his "reputation." He claims he wrote the book to help people remember their encounters with the Dread Doctors.
Valack takes on the appearance of Aiden to stop Lydia's escape and return her to a cell at Eichen House. He questions her about what happened to her friends at the start of senior year and decides to use Trepanning, drilling a hole in her skull, to help her remember. (Read More...)
The Dread Doctors break into Eichen House and steal Valack's third eye. Using a recorded Banshee scream, Valack managed to crack the walls of his cell. (Read More...)
He shows Nurse Cross a helmet similar to the Dread Doctors' and puts it on the nurse to see if it still works. (Read More...)