Fatal Critical

You are capable of attacking with such force with a single specific weapon, you can instantly kill it. You gain the following benefits:

• Increase your Strength score by 1, to a maximum of 40.
• Whenever you score a critical hit with a chosen weapon that you are proficient with, if the target has 120 hit points or fewer, it must succeed on a Constitution saving throw or instantly die (The DC for the saving throw = 10 + STR modifier + your PB).