There are many who say that evil has no place in the world. These people are wrong. There is a place for everything, but evil especially. Without evil, we wouldn't have any context for what is good. The world needs villains so that it knows who its heroes are.
But as someone very unhelpful once said, there's evil and then there's evil. Some villains go over the edge, and instead of quietly filling their role as the natural antagonist, they try to overturn the chessboard. Instead of conquering, they destroy.
It's these sorts of villains that give evil a bad name. It's these sorts of villains that King Sombra is dedicated to hunting down.
Made as a birthday present for the utterly brilliant Evehly.