Deeply immoral and wicked 

Depraved, immoral, malevolent, wicked

Mental disorders (antisocial personality disorder, psychopathy, sociopathy)
A history of cruelty, abuse, or neglect
Failure to form important relational bonds as an infant or child
Hatred for oneself or others
Altered brain structure and chemistry
Brain injuries
Having role models who used cruelty as a means of gaining power
Indoctrination or brainwashing that convinces the subject that evil is good and vice versa

Seeking out good wherever it exists and destroying it
Consistent sadistic and destructive behaviors toward others without remorse
Playing head games with people to emotionally torture them
Encouraging others to be cruel
Acting out of a lack of empathy and absence of morality
Preying on those who are vulnerable or helpless
Believing oneself to be above the law
Deliberately confusing others and their sense of values
Making people feel or look stupid in an attempt to set them on a self-destructive path
Purposely humiliating others
Playing cruel jokes
Bullying that terrorizes
Worshipping the devil or other negative forces
Getting to know someone for the sole purpose of exploiting their weaknesses
Leaning in closer to watch someone or something suffer
Becoming aroused (sweating, quickened breaths, bright eyes) while watching someone in pain
Committing acts of violence towards animals
Mutilating, raping, and murdering
Hurting living things because one can
Feeling alive through causing death
Overconfidence; having a God complex
Difficulty connecting with others
Complete disrespect and disdain for authority
Spending a disproportionate amount of time thinking up ways to hurt people
Committing mass murder and genocide
Experiencing arousal at the sight of blood
Being preoccupied with religion and how to subvert it
Enjoying the sounds of pain (screaming, crying, pleading, etc.)
Deliberately turning something benign into something monstrous
Taking excessive pride in one's accomplishments; wanting to be exalted and remembered
Being fascinated with weapons, blood, and stories of violence

AGITATION, ANTICIPATION, CONTEMPT, EAGERNESS, EXCITEMENT, HATRED, HURT, INDIFFERENCE, SMUGNESS

Many evil characters are quite intelligent and creative. They're good at reading people, and they know just what to say or do to stay out of trouble and win another's trust. While often incapable of empathy, evil characters understand the power of emotion and are able to mimic it well enough to fit in and manipulate others.

Evil characters are morally deficient, with little or no guilt or conscience to hold them in check. They do whatever they please, for personal motives or for the sheer pleasure of hurting others. Evil characters make good villains because of their willingness and desire to do terrible things, but it doesn't mean that they have to be all bad. Give your villain a gut-wrenching history, some positive attributes, and a cause he believes to be just, and he will become more complex and interesting.

After the violent death of his unborn child, John Kramer (Saw) is pushed to the edge of sanity. As Jigsaw, he embraces a dark alter ego, seeking out and capturing those who have done harm during their lives. He forces his victims into painful, unthinkable moral dilemmas where they're forced to answer one question: How badly do you want to live? Other Examples from Literature and Film: Rhoda Penmark (The Bad Seed), Randall Flagg (The Stand), Voldemort (Harry Potter series)

Some depraved characters can be rehabilitated by identifying and confronting their extreme lack of empathy. While therapy may seem trite and over-applied, it's usually necessary to control a problem of this magnitude. Unfortunately, evil is progressive, and many truly wicked characters can't be saved. It would be difficult and unwise to trust the Jigsaws, Adolf Hitlers, and Jeffrey Dahmers of the world with others; for people like these, death or removal from civilized society may be the only responsible recourse.

HONORABLE, JUST, SPIRITUAL