Stunned

Stunned is a status effect that can be gained in combat with NPCs, or inflicted by you. A stunned character will be displayed with a  blue  background color, and when a character is stunned, a special message will go along with it, which is You/Sterina Bella (some random NPC name) send(s) the zombie (or anything else) reeling for 56 damage! or something like that. Movement for stunned characters will be random, so a stunned zombie can be mistaken for running away, and he will bump against obstacles, losing 100 movement points.

This status effect is inflicted when you or an NPC get(s) a critical hit with unarmed Scorpion style or any style with knock back attack. It can also be inflicted by a weapon with the techniques, Precise Strike and Brutal Strike. The fire axe and the cudgel is a good example, but it relies on your melee skill as well, which increases critical hit chance in the first place.