I'm only explaining the damage ratios in this.
First thing, you role the dice for your particular weapon, those haven't actually been established yet, but Yeah. Each weapon, form, or spell, can do a different range of damage. At the beginning of your post, you Role Play what's happening, and then you role it's effectiveness. Another thing, is right before you RP, if you're in a battle, you roll the dice for your armor covering the part of your body that is being attacked. If it's number exceeds that of your opponents, you dodge/block/parry.
Health levels are yet to be decided.