Everything in Henriksen's profile on the Winchesters should be made into a new Showtime TV series.
Think of that AU brilliance. Sam and Dean, cult serial killers. Sam is Bonnie to Dean’s Clyde. Grew up with a father who was a post-war survivalist nut, moved them around motels and backwoods cabins. Brainwashed his boys with all that devil talk and no doubt touched them in a bad place. Smart, expertly trained, deranged. Prone to desecrating graves and getting sadistically creative on their victims. Sociopathic/psychopathic tendencies. Superficially charming–use good looks and false mannerisms to ease suspicious minds and ensnare victims. No known weakness outside of each other. Can be best identified by two matching tattoos of an unknown cult symbol on chests, likely a form of devotion to their cause, each other, or both.
If caught, use maximum precaution to restrain them as they have been known to escape multiple times. Best bet is to separate them as soon as possible. If you catch one, take caution in trying to lure the other one out by holding him hostage. One wrong move and you will be worse than dead.