For as long as there has been a world [or planet] conqueror, a criminal mastermind or some kind of fiendish intellect, they always need hired help. A henchman, or henchwoman, works along side their boss on their diabolical and nefarious plans no matter how much he or she is getting paid. They can be viewed in two stereotypes: the incompetent, imbecile who is often superstitious and accident prone and then there's the competent, loyal, and merciless partner in crime who follows orders without questions. Henchmen are often recruited in shady places and can be viewed upon as an 'evil sidekick'. Henchmen are also often required to wear matching uniforms that often reflect their boss' costume. Other times, they just wear causal clothing instead of a uniform. Aside from human or mutated henchmen, they can also be animals, robots, cyborgs, androids, clones, or even demons and aliens.
There are rare moments when a henchmen betrays their boss and are often killed off in retaliation. Other times there is a rare a moment for a henchmen who wants to renounce a life a crime and switch sides or simply walk away from crime forever. For example, Cal Durham was one of Black Manta's henchmen who left after Manta's cause when he became more obsessed with destroying Aquaman than establishing an African-American dominated underwater society as he promised.
Henchmen have gone by many names: goons, minions, cronies, lackeys, flunkies, underlings, subordinates, stooges, foot soldiers, and bodyguards.