Sinn is Killface's sexy female servant. She has a mechanical arm, replacing the one that Killface ripped off, and her speech has an electronic effect. Sinn is romantically involved with Arthur, and often refers to Killface as "Sire."

When Killface fires Sinn, replacing her with "Barnaby Jones" (Xander Crews), she joins the Xtacles under the alias of Hooper. The Xtacles are attracted to her, and she used this to control the group. She is shot by Valerie after attempting to have sex with her.