Destroyer of Innocence

A Destroyer of Innocence is a type of villain who is responsible for a "loss of innocence". A "loss of innocence" is when a sympathetic and (usually) somewhat defenseless character is broken or harmed in some way or similar; this often invokes great feelings of anger by audiences and marks a common Moral Event Horizon. It can also refer to an event that causes unprecedented outrage in society, such as child murder and terrorist attacks, which challenge our concepts of what people can do to each other.

Destroyers of Innocence are villains who effectively "destroy" the innocence of a story, setting, or character; they are often especially wicked beings who ruin lives and their crimes can never truly be reversed as it erases the concept of "innocence," though some rarer examples do not fully know they are responsible for this occuring.

A Destroyer of Innocence is the evil opposite of a Protector of Innocence.

Examples of this type of villain are as follows:

1. Any character who abuses/corrupts a child or someone with a child-like mentality. (Many "Fagin" types fall into this category). Example of this are Medusa Gorgon, callous witch whom abuses Crona to the point that Crona became mentally disturbed.
2. A character whom a protagonist has admired deeply in the past (even without their knowledge); upon learning of the character's true nature, the protagonist is visibly distressed. Examples of this are Charles Mutzu from UP or Lance Preston from Grave Encounters.Sōsuke Aizen from Bleach also is such a villain, having shattered Momo Hinamori's trust in him by betraying the Gotei 13. 
3. Characters who betray loved ones, family, or friends, especially if their betrayal is brutal and treacherous in nature. (A good example would be Scar's betrayal of both Simba and Mufasa in The Lion King.)
4. A character who masterminds a particularly shocking event (such as a terrorist attack or massacre of innocents) which in turn causes a deep and lasting "loss of innocence" in his or her setting. The event itself can also count if it has profoundly challenged people's perception on the world. A example of this type of villain would be Isaac Ray Peram Westcott from LOTM: Sword of Kings which caused the death of over millions of people in his wars and turned an universe into a battlefield, killing billion of people, also as destroying entire realities and killing his own daughter.
5. A villain who apparently seems to be harmless or even innocent, but it is only one facet to hide its nature and can easily commit atrocities. (Eric Cartman lost his innocence since he killed Scott Tenorman's parents in the South Park episode "Scott Tenorman Must Die.")