Help with combat - Defense not translating to combat?

[Wishboi]

Hey, this is the most noob question ever but I just can't figure it out. So I made some armor that increases defense by 5, and yet despite equipping it or not, my NPC does the same damage regardless. Here are what my NPC and item editors look like.

 

[Cheshire]

I believe the default combat formulas don't work very well in general and are a bit skewed.

 

You'd have to change those around in the formulas file on the server side to make it work with lower numbers.