Tate was born in 1977 to Hugo and Constance Langdon in Atlanta, Georgia. Tate was the brother of Adelaide, and Beauregard. He's the only one out of the three not burdened by some sort of mental or physical defect, although he is psychologically disturbed. This is due largely to his father's absence and his mother's neglect as a child.
Tate's homelife as a child wasn't pleasant. His mother, Constance, left his father after having an affair with the neighbour, Larry. As well as having that weight on him, the 7 year old Tate had to deal with being ridiculed at school for having a sister with Down Syndrome, and persistent verbal abuse from his mother. A couple years after, Tate's brother was murdered by Larry, who moved into the house to try to play the part of a father in Tate's and Addie's lives. Larry and Constance are unaware that Tate knew what really happened to his brother.
In 1994, something in Tate snapped. He did large amounts of cocaine before heading out. Before going to school, he went to Larry's work and set him on fire for murdering Beau. Then he headed to Westfield High to commit a mass homicide, killing 15 students and sending an unknown number to the hospital.
He goes back home. The SWAT team managed to track down the shooter and storm up to his bedroom, ignoring Constance's cries for mercy. The door to Tate's room slams open and Tate is sitting on the bed, waiting, smirk on his face.
The SWAT team trains their scopes on him, and he mimes putting a gun to his head..... Before diving for a gun hiding under the pillow. Before Tate has a chance, the SWAT team shoots him, killing him in an instant. His spirit, as well as many others, resides in the house.
Once Josh, Andy, Jordan and Annabeth move in, only then do they find out the gruesome and macabre history of the house. Unfazed, they chose to stay. Once and a while, the ghosts will come out to interact with the family and guests. Tate comes around most often though, finding solace and friendship in Jordan.