In the end everything is relative.

Imagine a society of people where many of the concepts that rule our society simple don't exist. It's just dog eat dog and that's the norm. You wrong me and I take retribution on you and yours and that's just the way it is. You're walking down the street and the guy next to you keels over and people just leave him there to die, no one cares that's just the way it is.

We define ourselves based on the norms of our society. That's one of our big problems because if there is a clash of our societies we need to reconcile what we might think is universally evil to what another society says is the norm and the law. I think you all know what I'm getting at here without having to say it.

We have people within our own society who we say are anti social or nonconformist who play by their own rules not ours. Many of these people we might say are evil.

I challenge you to come up with any single action or concept that any intelligent living being be he from this world or another, could universally agree on as being what we generally think of as evil.