Frank

Frank is one of the Guys alongside Guy in the title. He wears glasses. He was first talked about off-screen in the first few panels by Guy and Wayne as having fought a child over a cupcake. He first appears with icing on his mouth, indicating that this is true.

The cupcake reference returns later although they are referred to as "muffins" it is clear by their illustration that the muffins are pink-frosted cupcakes with a cherry on top.

The observation by the schoolgirls indicates that Guy and Wayne may actually not exist and could just be symptoms of Frank's insanity, something touched on earlier.

He is insane, the perfect mad scientist. He has no morals, and no qualms about killing people, something that his friends seem to share.

Trivia

 * Frank does not sleep