Consider the extreme example of a person exerting all efforts to defame people around them, whether in work or their own social group, collecting innocent emails and letters from people and later trying to use them as an evidence that those people have lied and are corrupt or 'unworthy'.
However, they go to all lengths to protect their own integrity and 'uprightness' by comparing themselves to the so-called liars and unworthy people by always mentioning their own good points etc.
I thought about 'Character assassin' or 'defamer' but it doesn't seem to give the full meaning.
Is their not a word / term used by psychiatrists to describe such a person?