And here's what about Satanists!...
They believe that Judas did a good thing by betraying Jesus. And that Jesus himself asked to be betrayed. And he (Jesus) was crucified. And in doing so, human sins were redeemed (I don't remember exactly which sin, perhaps the original sin)...

But that's just a side note, since we're talking about the Bible.

And where there is good, and where there is evil - is a complex question, and almost unresolvable (for the general public), because everyone has their own rightness and their own perception of the world (it is still possible to find where good and where evil are for a specific person).