Mad scientists and geniuses gone mad have been the villains in many cartoons. Murderers, psychopaths, serial-killers, and terrorists have been the bad guys in many books and movies. Perhaps one of your characters has a psychotic personality.
A quiver is a container for arrows. As a verb, quiver means to tremble or shake slightly. A group of geniuses - I like to think they would be evil genuises - is known as a quiver of geniuses. Perhaps these evil geniuses enlist the help of a mad scientist or two. Maybe these evil geniuses even turn into mad scientists themselves.
A mad scientist is an inventor or scientist whose insanity endangers himself and others. Can't you just see a mad scientist, thrilled with the evil discovery that he has made, leaning over his horrible experiment, wringing his hands, and cackling with glee? Could this be why a group of these evil, diabolical, and mad scientists is known as a cackle of mad scientists?
An event that really happened comes to mind when I think about a band of murderers. What comes to mind is the horrendous murder of actress Sharon Tate by Charles Manson and his followers. Think about it, though, a band of murderers? A band of murderers goes on a killing spree, then they all stop and pull out musical instruments to compose and play a song in honor of the atrocities they have just committed?
A psychopath is a person with a serious mental illness that that causes them to behave violently towards others. You can carry stuff to be thrown in a sling; when you throw these items, you sling them. More than one psychopath, known as a sling of psychopaths, would just aimlessly sling around their unwarranted violence.
A psychopath is a good candidate to become a serial-killer. I wonder, do serial-killers associate with each other? Do they have meetings where they discuss the newest, cruelest, and most effective ways of killing their intended victims? Would a choir of serial-killers would meet and sing songs about how they murdered their unsuspecting victims?
Just in case you don't know what a terrorist is, it is someone who uses violence in order to achieve political aims. More than one of these violent individuals in known as a cell of terrorists. A cell, besides being a place where a prisoner is kept, is defined as a small group of people who work together as members of a larger organization, often a political one.
In an industry, a group of people work together to achieve a specific aim. An industry of villains would work together, but what they are seeking to achieve would be against the law. Maybe the industry of villains is working together to overthrow an already established industry in a large city so they can use the industry for their own diabolical plans.
