Evil is defined by traits of immorality and cruelty. Being evil is part of being a villain and part of the traits in villainy altogether. Not all evil characters written are villains as these characters lack villainous deeds and fails the heinous standards to be considered villains. Evil characters that are evil without villainy are often portrayed to be jerks or mischief-makers. Heroes may also have traits of being evil and can be capable of doing evil things, though rarely to the same extent as villains.
On the Moral Spectrum, Pure Evil (Rank 1 -) characters are absolutely evil and stands out as the most heinous and wickedest character in the Moral Spectrum. These villains may have had good traits in the past but became wholly debased over time to completely become evil.
Pure Good (Rank 1+) characters are completely devoid of any evil traits and have committed the most admirable acts that benefited many individuals. These heroes may have once had evil qualities but over time have subverted them.