Child Murderer

For many the killing of people who are 12 years old or younger is not only an instant Moral Event Horizon but also goes against the very concepts of what we see as basic humanity (even if the murderer is a child too, or if the child was a villain themselves since villains who are children are much easier to rehabilitate) - for this reason villains who are portrayed as willing murderers of children are reviled far more than those who kill teenagers and adults: in the past the killing of children was an extremely taboo subject matter in fiction, though it has become more common (though no less controversial).

This is not to be confused with a villain that has murdered their offspring (as they are a Family Murderer instead), though it is possible for these two categories to overlap.

Note: Do NOT add characters who only killed teenagers and/or adults in this category, as teenagers and adults do not count as children.