A principal enemy. Specifically, Satan, the grand adversary of mankind.

An archenemy, archfoe, archvillain or archnemesis (sometimes spelled arch-enemy, arch-foe, arch-villain or arch-nemesis) is the principal enemy of a character in a work of fiction, often described as the hero's worst enemy (compare ). The reason as to why the particular villain stands out more than the other rogues gallery villains varies, although they may be the hardest enemy to fight, the hero's opposite, the most often recurring villain, always bearing the most dangerous plots or poses the biggest threat, such as global domination in comparison to burglary, was once a friend of the hero, or is the source of constant tragedy, pain and horror to the hero.