I am making me a sword, and i want to make it have a 5% chance of killing the target, and on a kill hit, it has a melfs minute meteors effect on them when they die, i can make it kill them on a 5%, but im not sure how to make it do the effect only when it kills them, not with every hit.

I also have 50% chance to slow them opponent
35% chance to knock them unconscious,
does this matter?