Concept: When you get enough insight with the Impurity rune, Valtr changes. He becomes a writhing mass of vermin and flesh with heavily stained Constable clothing clinging to his form like wet tissue. His arms have too many joints, and his fingers, reduced to phlegmy tendrils, seemed fused to the handle of his whirligig. His voice is warped and sounds like worms squishing together with every syllable. Something oozes from the hole in his helmet, and sometimes vermin writhe out only to fall and crawl back up what’s left of his leg to the main mass.
But despite the changes to his appearance, Valtr himself doesn’t change. He’s still the Master of the League and a fellow hunter.
He lost the ability to see vermin and the impurity of man long ago, and perhaps that’s for his own good.