I feel like suggesting this:

If there is such a "thing" as evil, it doesn't generally look evil and it actually probably often looks "pretty cool" (in the sense it's seductive and it probably has to do with being relaxed about grave things: a kind of self satisfaction in denying urgent issues and not taking any responsability). That's our evil, the evil we put up with and indulge in every second of our lives at this day and age: being pretty cool in a world that fundamentally is not! (instead of doign something)

Maybe someone already wrote something similar to this previously: if that is the case I'm sorrry for the repeat, but I didn't take the time to read all the other answers yet.

I think I wrote this, because I sensed that the danger of dealing with evil on stage is to make it too obvious, something like a Walt Disney-baddy portrayal : there are all sorts of clichés around "evil" and it's probably very different to get rid of them and produce something different and "clearer".

Good luck