Not bad-though the Haazekthok has pretty low ability scores especially considering its gargantuan size.

Is their Greater Teleport ability limited to themselves or can they teleport others too?

Why a rage ability? Rage is not an ability that reflects Law at all in its flavor. You can give the same bonuses via a "killer's persistence" ability that gives a +3 cumulative bonus to strength, constitution and will saves each round the combat continues to a maximum of +9 (to reflect the Nine Hells) so it really fits with the flavor.