From Homicide: Life on the Street. aka The Forces of Eeeevil The Dark Side etc. Love spelled backwards, it describes any villain who does something only for the sake of being evil, or serves evil (as if it were a Union or something.) As opposed to merely greed, ambition, or other vices. Example: Gul Dukat from Star Trek: Deep Space 9 wasn't evol at first. He did the atrocities that he did out of greed, ambition, and misaligned patriotism. When he became the conduit of the Fallen Prophets who wanted to destroy/dominate the universe just because they believed in serving darker emotions, he became Evol.
EVOL
Meaning of EVOL in English
Slang English vocab. Английский сленговый словарь. 2012