In theory, a body ten steps below Fair has no health levels, but then a body that low shouldn't be biologically feasible in the first place. Wounded characters get pain penalties. Near Dead and Very Hurt characters will heal a health level from every severity once a month. Hurt characters heal once a week. A character with nothing but Flesh Wounds heals daily.
Speed is used for initiative.
Mind is used to keep from freaking out at bad moments. Some GMs might change the difficulty with the severity of the stress. Soul has no specific task, but is used for mystic resistance and sensitivity. If they succeed, they will deliver a wound, with the severity based on the level of success. A result five steps up is lethal.