Arcman
Heh
But the ones on the verge of turning into beasts have a distinct lack of fear, relatively speaking. They become extremely reckless, aggressive, and relentless. They care more for seeking more blood than any fear they might have left.
Ludwig's Holy Blade gave him a sort of false reassurance, and so he was blind to his going too far and too recklessly in his pursuit of beasts.
That, and he wanted to deny what the Church Hunter's were becoming.