Simon is a biochemist and assassin who decides to kill Werewolf by altering canine distemper. He transfers the virus via ink pads.
Simon acts as a proctor for the PSATs at Beacon Hills, where students have to sign in by giving a thumbprint. His discovers Stiles figuring out how the virus was transferring in Coach's office and demands that Stiles tell him where Scott, Kira, and Malia are or he's going to shoot him. Simon puts a gun to Stiles's head, but is killed by Rafael McCall before he can pull the trigger.