How to fight
During Leon's first encounter, use the button combinations that appear on the screen to defeat Krauser.
During Leon's second encounter, the knife is a handy weapon for battling Krauser up close. few slashes will send him running to the next area. The rifle is a good weapon for when he shoots at you from far away. When he mutates, button combinations will show up on screen to dodge his attacks. When not doing this, a few slashes with the knife will bring him down. The same strategy applies to Ada. The weakness against the knife is one which only Krauser has, so it is recommended that you only use the knife against him.