Taint mechanics (Ravenloft campaign, maybe others)
Some vile sources exist that are capable of corrupting your character’s body or maddening his mind beyond the normal capabilities of restoration via natural healing of Extended Rests or conventional medical care.
Possible sources of Taint include various creatures or environmental hazards.
Taint is measured in points.
Madness – Mental taint. Will defense serves as a bulwark against it.
Mutation – Body taint. Fortitude defense protects against it.
Taint – The amount of Taint points you accumulated since the last Extended Rest.
Taint Attack Roll – When your character is exposed to taint source, he attempts to resist it with his sheer physical or mental endurance. The roll is d20+Mod vs Fortitude for Mutation Taint, or d20+Mod vs Will for Madness Taint. The “Mod” is determined by DM, and usually is close to attack roll for implement attacks of the monster of level equal Taint source in question.
Taint Resist Roll – d20+New Taint vs 10+Existing Taint. Resist new incoming Taint with the Taint you already have. On a “hit”, the Taint stacks. On a “miss”, the Taint does not stack – the biggest one of two values (incoming and existing) become the current character’s Taint. Think of this roll as a check, whether your character already has that particular sort of Taint on him.
Corruption – The amount of surplus Taint points that were not removed during Extended Rest, multiplied by 0.5 (rounded down). These points attempt to become engraved in your character, which is reflected in the Corruption Roll made at the end of Extended Rest.
Corruption Roll – Roll d20+Corruption. Depending on the results, you may or may not acquire new Corruption level and corresponding Corruption Feat.
Acorn – magical item, which is used during Extended Rest. They allow your character to spend any remaining Healing Surges to remove Taint Points accumulated since last Extended Rest. Every HS spent that way reduce the amount of Taint by 2.
Examples of mechanic in action:
Brawny the Level 1 Fighter is our adventurer. His defenses are AC 16, Fort 15, Ref 11, Will 13.
Brawny walks into pool of radioactive bile. He already has 2 points of Mutation Taint.
Radioactive bile attempts to inflict 1 point of Mutation Taint every round, + 5 vs Fort (exact numbers are DM’s call).
First Roll, taint attack: d20 + 5(Mutation) vs 15(Fortitude). On a miss, nothing happens, no taint, no damage.
Second Roll, taint resist, occurs ONLY if First roll hit: d20+1(New Taint) vs 12 (10+existing Taint). On a miss, Brawny’s Mutation Taint remains at 2. On a hit, it becomes 3.
Brawny is engaged in combat against a screeching banshee. Brawny already has 1 point of Madness Taint.
Banshee’s Sonic Wave is a + 6 attack against Reflex. On a hit, it inflicts 8 damage and attempts to inflict 2 points of Madness Taint, rolling + 5 vs Will defense (again, those numbers are DM’s call).
Roll 1: Attack Roll. Brawny is targeted by Sonic Wave: d20 + 6 vs 11. On a hit, Brawny suffers 8 points of damage and Roll 2 occurs. On a miss, the miss effect of Sonic Wave occurs, which is, apparently, nothing.
Roll 2: Taint attack roll. Occurs only if Roll 1 was a hit (because there is no “miss” entry on Sonic Wave power card mentioning any taint infliction). d20+5 vs 13. On a hit, Roll 3 occurs. On a miss, nothing happens.
Roll 3: Taint resist roll. Occurs only if Roll 2 was a hit. Brawny attempts to resist new Madness with his existing Madness. d20 + 2 vs 11. On a hit, Taint stacks and Brawny will have 3 Madness Taint total. On a miss, Taint does not stack and Brawny is left with the biggest of the two – in that case, 2 points of Madness Taint.
Brawny prepares to take Extended Rest. He acquired 3 Mutation Taint points and 4 Madness Taint points during this adventuring day. He has one Acorn and 3 Healing Surges.
Brawny chooses to spend his Acorn and all of his remaining Healing Surges to get rid of as much Taint as possible. First, he decides to spend 1 HS to remove 2 Madness Taint and 1 HS to remove 2 Mutation Taint points. Now, Brawny faces a choice – he can spend his last HS to either remove 2 Madness Taint points and complete his ExtRest with 1 Mutation point, or to remove 1 Mutation and 1 Madness point and complete ExtRest with 1 Madness point.
Finally, he decides to get rid of Mutation completely and proceeds with Extended Rest with 1 Madness Taint remaining. He has to make a Corruption Roll to see whether that Madness engraves deep enough in his mind to cause some more permanent damage.
Corruption modifier = Taint/2, rounded down. In this case, its 0.
Thus, Brawny makes Corruption roll of d20+0.
If his d20+0 rolls 20+, his Corruption:Madness severity level is increased by 2. If that level was 0 (Completely Sane), Brawny contracts Moderate level of Madness. Exact kind of Madness and corresponding Aberrant Feat is determined by DM.
If his d20+0 rolls 15 or more, but less then 20, Brawny’s Corruption:Madness severity level is increased by 1. If that level was 0, Brawny contracts Slight level of Madness. Slight level usually comes with some relatively small disadvantage and without any Aberrant feats.