|This discussion contains fan theories about the motivations of Tate Langdon. It is separate to avoid contaminating the main page with spoilers and speculation. It is subjective.|
| The house exerts demonic influence on men
Hugo raped Moira. Larry murdered Hayden, and Ben just covered it up by building a gazebo. Larry killed Beau, acting on Constance's instruction. Tate shot 15 people. NOTE: After Larry killed Hayden, Ben did have an emotional reaction to her death, so this theory may not hold up.
| Tate's family is severely dysfunctional
This theory is, of course, not mutually exclusive with Theory #1. Which could lead him to his drug use.In the 10th episode, "Smoldering Children", there is a flashback of the Langdon family and Larry all having dinner. Constance yells at Tate for saying she doesn't love Larry. Their argument ends with Tate saying "No matter how much you want it I will never be your perfect son". Next it shows him turning off his alarm already awake. He is then seen snorting a white powder (Cocaine) and then grabbing guns from under his bed. He then sets off to set Larry on fire and shoot up his high school. It is well established that cocaine, especially in large doses over a short period of time, can make the user very violent.
| Addie was bullied
Addy was bullied and/or molested; Tate was seeking revenge. Addy was in her 40s when she died. When Tate was a teen, Addy would have been already out of high school. And knowing Constance, she probably didn't even send Addy to school. It is still possible for students to have bullied her outside of the school.
| || There was more than one killer