|intentional harmer (n., adj.)|
An intentional harmer is a headmate that harms other headmates.
They may believe bringing harm including, but not limited to, sexual, physical, or mental harm, is a good way of showing other headmates that the world is not good, safe, and/or happy. It may also be a way that these headmates attempt to get control in their system, or an attempt to disrupt the peace.