Question stun in a skill with case

Problem with your example is that you stop fighting if you get < POS_STUNNED


Where I want the victim to become stunned no matter how many HP they have. So the attacker can just keep fighting them without taking damage. Or stun the victim to let a low level char attack the mob

Yes, I am saying those are the issues that you'll need to solve to have it work correctly because a lot of that is what is already in the code.  I'm just showing the example as a way to help you get to that goal.

I really don’t see what is wrong. As far as I know it should work. But it doesn’t

Because there are those instances in the code that "fix" POS_STUNNED after it you set it, at least the way stock code is.  If you check the value in your code at various point, the value of POS_STUNNED was indeed set, but the default code doesn't really allow for someone to stay stunned in combat unless they are low health so it resets it.