Brandon

Brandon is played by Ty Fuhrman. This page contains discussion of suicide.

Season Three
Brandon is a member of Aurora Silver's cult. He shoots Mabel Martin with an iron bullet and then shoots himself in the head. His body is eaten by the House.

He's consistently referred to as "young man" or "kid" by the other characters, suggesting he's somewhere around 16-18. The author of this wiki unironically adores the cult boy and wishes he'd survived and also didn't shoot Mabel, because if he's that young it probably means it wasn't his choice.