Agatha's great-great-great grandfather, Iscarriot Heterodyne, "Everyman's "Friend" (he collected at least the craniums of 101 of them), was an infamous madman and despoiler of peaceful villages. Interestingly, Iscarriot's madness seems to have cushioned his self-image, convincing himself that he was a something of a "people person."
Described by the Jägermonster Jenka as "diff'rently shmot," Iscarriot's first experience leading Jägerkin into battle ended with the entire raiding party falling off a cliff - which he then explained was part of the plan to begin with! This could indicate that Iscarriot was less intelligent than his Sparky relatives, that he inherited more than the usual quota of Sparky insanity, or that he really didn't like admitting error. The reader may reach their own conclusions.
Obviously, "Iscarriot" Heterodyne was named after this infamous personage.