I think a good combat system would be to have a variable for the heroes life such as 10. And then add a variable for NPC health. Add a variable for defense and dodging added by armor. Then another variable for the equipped weapon of both npc and hero. Make it roughly turn based, in which it is not in a separate map but rather one hits then the other. I believe this would be a realistic and easy to use combat system.
-Elliot K