Wounds

Overview
Wounds represent significant damage to a creature, and usually occur as the result of a single high damage attack or a critical hit. Wounds cannot be caused by Psychic or Non-lethal damage.

What Causes Wounds:
Massive Damage: if a single attack would do more than ½ a creatures max STA the target suffers 2 wounds. Failed Death Saves: A creature suffers a wound on each failed death save. Wounds do not affect death save rolls. If a creature is stabilized, they still have the effects of their wounds. Critical Hits: A critical hit always causes a wound unless an ability, item, or spell says otherwise. 

Wound Mechanics:
A creature can suffer a number of wounds equal to 3+base HP+CON modifier before they are killed. When a creature reaches 0 wound points, they die. Each wound subtracts from your current wound points. Your current wound points tell you what effects they give you.
 * For all points. Max stamina is reduced by 1d4 x character level (or CR for monsters) for each wound point under the max
 * 4: disadvantage on ability checks
 * 3: speed halved
 * 2: disadvantage on attack rolls and saving throws
 * 1: speed reduced to 0
 * 0: death


 * <p dir="ltr" role="presentation">To heal from wounds: simply taking a long rest recovers 1 wound, and a successful heal or engineering check can allow you to recover an additional 1d4 wounds. You or an ally must have 1 interrupted minute to perform the check if you make it. The DC is 20-CON modifer of the creature being healed.
 * <p dir="ltr" role="presentation">Wounds can also be healed via Spells, abilities, and potions that would normally give you HP or Stamina points. You can heal 1d4 wounds per use in addition to the HP/Stamina healed.

For the sake of simplicity, enemies have STA, with HP equal to their CR (per creature, min 1) and have wound points equal to their CR(min 1)+con modifier (min 1). So a goblin would have 7 STA and 1 HP, with 1 wound point (¼ CR, +0 CON), and a standard Beholder would have 189 STA, 13 HP(CR 13), and 17 wound points (13 CR, +4 CON).