"Ultimate evil" refers to the most extreme and morally wrong actions or behavior that a person or entity can possess. It represents the highest level of wickedness or cruelty. Full definition
Some training, trials, and a crisis of self - confidence later, he emerges as the true hero ready to defeat ultimate evil. (theatlantic.com)
Join the crusade against Death itself and face ultimate evil in the definitive Diablo experience. (punkandlizard.com)
But then you'd miss the joy of watching Michael Cera get a phonecall from the legend that is Jason Schwartzman, here appearing as ultimate Evil Ex nemesis Gideon Gordon Graves, with some rather upsetting news. (empireonline.com)