He is on the "Children of Dranik" faction, you take a hit when killing him.
It also says your faction with "Overlord Mata Muran" cannot get any better so that must be opposing faction. Of course killing stuff on "Overlord MAta Muran" faction gets you the message that your faction with him cannot get any worse, so I guess its a fixed faction that cannot go up or down, he just hates everyone and theres nothing you can do to change that. =)