From the publisher's description:
A demon gave you superpowers and it demands EVIL. Maybe a little over-the-top, thwartable villainy will keep it under control. Maybe.
In Better Angels, each player takes the role of a once-ordinary man or woman who's been possessed by a demon that granted superhuman powers. If you're one of the possessed, the demon demands that you perform horrific acts of evil. But it's tough. You don't want to do the really evil sort of evil, right? But if you refuse it altogether, the demon might leave and haunt someone else. Someone who wouldn't mind atrocities so much.
So you find a way to compromise. You act like -- well, you act like a supervillain. You come up with these huge, grandiose, ridiculous plots to rule the world and steal all the money and corrupt all the minds, exactly the stuff that your demon wants to do. What you hope the demon doesn't figure out is that it's all so ridiculous that the superheroes are almost sure to stop you. When they do, the demon's evil will be thwarted. With any luck, nobody has to suffer any atrocities at all.
Did I mention the superheroes? There are superheroes. They're haunted by superpower-granting angels. They're out to stop you. This game is not about them.