Please tell me any works of fiction you know in which the main antagonist (or at least a major antagonist) is a child.

I have only two limitations on what I'm looking for:

1) This is optional, but I would prefer to avoid the "creepy little ghost girl" cliche, i.e. Samara or Alma Wade

2) I'm looking for things that are fairly serious in tone. I don't want something like Mandark from Dexter's Lab, or Angelica from Rugrats.

The movie The Children and the video game Rule of Rose would be examples of the kind I want. It doesn't necessarily need to be in the horror genre, though I guess that's where most would be.