During the second Krauser encounter, after you get two Sacred Beast pieces and go to the tower, u will be fighting Krauser. Use only your Knife. when he charges normally, slash at him before he hits you, he will then pause flinch, hit him more times as he does so. continue this, along with dodging the "L1+R1" and "square+X" attacks. You should kill him on the third or fourth time of stopping him.