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 himself in the head in Temporal Snake, which ricochets off of him and hits Mabel Martin in the arm. His body is eaten by the House and is later dropped in front of Anna and Mabel before a snake comes out of it.

He's consistently referred to as "young man" or "kid" by the other characters, suggesting he's somewhere around 16-20 (confirmed in a post by Becca De La Rosa).