Each character starts off with VP equal to their Constitution score plus HP increases due to things like the toughness feat and multiplied by a size factor.
Colossal 8
Gargantuan 4
Huge 2
Large 1
Medium 1
Small 1
Tiny 1/2
Diminutive 1/4
Fine 1/8
If a monster doesn't have a CON score, its VP is also 0. Quite likely, it is also immune to critical hits. When its HP is reduced to zero, it is dead.
VP damage occurs when HP is reduced to zero, with critical hits, or when CON is reduced. Only lethal damage can affect VP. Non-lethal damage only affects HP.
With every point of CON damage VP is reduced as well (no saving throw to avoid this VP damage). Thus if a character's VP is 17 (CON 14 + Toughness 3) and she is poisoned for 4 pts of CON damage, her VP is also reduced by 4 pts to 13. Her VP can heal back up to 17 even if her CON is still reduced.
When HP is reduced to zero, all damage becomes VP damage (no saving throw to avoid this VP damage). HP can't be reduced below zero. When HP is zero, the character is disabled, stable, dying or dead (see below).
When a critical hit is scored HP gets damaged as normal. For VP, the character must make a Fortitude save, DC 15+VP damage or take the VP damage. VP damage is the minimal normal damage for the weapon. For example, VP damage for a 3rd level Rogue (STR adj +2) using a Rapier +1 and a sneak attack would be 6 points: 1 (for the d6) + 2 (STR) + 1 (magic) + 2 (sneak attack).
When VP is reduced to zero, the character is dead.
VP heals slowly. It takes (7 - CON adjustment) to heal 1 pt. If your CON adjustment is 0, 1 pt of VP takes 7 days. If your CON adjustment is +3, 1 pt of VP takes only 4 days to heal. If your CON adjustment is -2, you'll have to wait for 9 days to heal one pt. As long as the character is able to eat, drink, sleep, and isn't fatigued, VP healing happens automatically. Under long term care, the amount healed is double. Under complete bed rest, the amount healed is doubled. Thus, a normal character (10 CON) under long term care and bed rest can heal 4pts per week (spread the points out over the week).
Magical or herbal healing heals HP as normal. In addition, VP is healed according to the adjustment to the die roll. For example, if the healing source gives 2d8 + 4 points of healing, the character gets 2d8+4 to HP and 4 to VP.
Healing CON damage does not heal VP.
Regeneration: Only lethal damage can affect VP. Thus wounds that can regenerate don't damage VP.
Fast Healing: If a character (or monster) can heal at a fast rate, VP that was cause by healable wounds (for example, starvation is not healable), heals at an accelerated rate. Instead of taking days, it will take hours. Plus, the number of points healed is the Fast Healing rate / 5 (minimum of 1). For example, a typical Five-Headed Hydra has a Fast Healing rate of 15 and a CON of 20. Thus every two hours (7 - 5 for Con), the hydra will heal 3 (15/5) points of VP.
When your HP is reduced to 0, you can be 1) disabled, 2) stable, 3) dying, or 4) dead. Hitting exactly 0 HP means you are automatically disabled. Otherwise, you are dying and need to make a saving throw next round.
A disabled character is stable and conscious (same as the standard definition).
A stable character is unconscious but not dying. In the standard rules, a character has a 10% chance of becoming disabled and a 90% chance of losing 1 HP. In this variation, that HP loss is VP loss instead.
A dying character needs to make a Fortitude save, DC 10 + rounds dying (not counting the round you first started dying). How much you save (or fail) by determines what happens:
natural 19-20: stable
save: still dying but no VP loss
fail by -1 to -10: dying, 1 pt VP damage.
fail by -11 or less: dying, 2 pt VP damage.
natural 1-2: dying, 2 pt VP damage.
A dead character is dead.
Falling damage: You take 1 pt of VP damage for each die of lethal damage suffered from the fall.
An example...
Bushnell Kite has 16 HP and 10 VP. His Fortitude save adjustment is +2. In the previous battle, he suffered 4 pts of VP from a critical hit and then he took a shot from a Cure Light Wounds Wand to bring him to max HP and 1 pt of VP healing. His current VP is 7. Poor Bushnell is attacked by a worg. In two bites, Bushnell is reduced to exactly 0 HP. Disabled, Bushnell is a sitting duck. One more bite for 5 pts of damage reduces his VP from 7 to 2. Bushnell is now dying. The worg moves off to attack someone else. The next round, Bushnell needs to make a Fortitude save DC 10 (rounds is zero). He rolls a 8 (6 + 2). He loses 1 pt of VP. He now has 1 pt of VP. Next round he rolls against DC 11. His total roll is 17. He's still dying but he hasn't lost any more VP. The next round he rolls a natural 20 so he is stable.
