There is some romance in the drama but it’s not a main focus, it’s more focused on revenge. I thought there would be couples formed but it never really happend. Seo Yi Kyung and Park Gun Woo was a pairing (with flashbacks in the past), and Tak really liked Lee Se Jin.
Not exactly evil, but these FLs start out as chaotic, haughty, arrogant, selfish, rude, jaded, dark, sociopathic, or villain / antagonist-coded in some other way, while the ML is coded as good: