The dark side

This phrase originated exactly as we all think it did. Star Wars, the brainchild of George Lucas, introduced society at large to the dark side through the character of Darth Vader. The phrase did appear in a 1650 publication from theologian Jacob Bauthumley but stayed out of use until Star Wars. Read all about it here.

The phrase also means just what we use it for, the evil side of a personality or society.