I'm looking for a word to describe someone who derives a feeling of glee from the success of intentionally hurting someone, and getting away with it.
The closest I can articulate this is as the attitude of someone who exhibits duper's delight.
"Duper's delight" is the delight that people feel when they deceive others.
But "duper's delight" is a phrase and not a word, describes a feeling and not a person, and doesn't have the element of cruelty.
The word I'm looking for is close to sadistic, but with a smug, gleeful attitude and childish impudence to it.