It's a noun and sometimes used as a sobriquet. In it's very essence killmaner is the result of the
words 'kill' and 'manner'. Latter is shortened to 'maner'.
The meaning is a person of such charm and charisma that he involuntarily and unassumingly draws everyone he meets to himself.
He is the alpha, the
omega and the sigma all in one.
Infact killmaner is not just a person, but a state of mind. A
way of living, and a philosophy.