There are many traits that make a character evil, so make sure to include the evil traits that will help foreshadow and emphasize the villain in your story.
Everyone loves a villain–the badder the better–and readers love to hate them, but writing them can be tricky, especially if they’re not obvious villains. There are plenty of clues to sprinkle about and chances to give both your readers and characters an inkling into their true evil nature.