Caustics fall into one of two categories: acids and bases. Acids are chemicals whose first atom is hydrogen, and whose pH value is less than 7. Bases are chemicals whose molecular chain ends with an oxygen-hydrogen pair, and whose pH value is greater than 7. By comparison, distilled water, whose chemical formula is H2O, has the structure H-O-H, and is thus an acid and a base at the same time, and therefore has a pH of 7 (which is considered "neutral".) Human blood is somewhat acidic, which is why an alkaloid poison (a strong base) is so deadly if ingested. Rainwater is also usually slightly acidic hence rust is possible. [Caustics|Buffers]
In combat situations, throwing an acid or base at an enemy can be fairly destructive. Acids have a detrimental effect on armour and weapons crafted from metal. The hydrogen component temporarily separates from the solution and causes the metal to become a metallic oxide. Despite popular myths, acids don't actually "eat" anything, but instead rapidly oxidizes whatever they come in contact with. Thus sometimes a vial of caustics is the best way to even the odds against an opponent who is armored like a Sherman tank. And acid will oxidize through metallic armour at the rate of 1 AC per intensity per round.
A base, on the other hand, will have a similar detrimental effect on organic items (leather, hide, etc.) as well as armour, wooden doors, bows, and so on.
Characters whom have had acids or bases thrown at them do not start taking damage until their armour has been destroyed. A caustic chemical has a primary damage effect that lasts for 1d4 rounds and a residual damage effect that lasts for 2d4 rounds thereafter. The "dose" for an acid or base is six fluid ounces. armour takes damage only during the primary effect. While rare, these fluids are actually fairly cheap. The cost is measured in glass pieces.
|Table: Effects of Caustics|
|Intensity||Name||Primary damage||Residual damage||Cost (gP)||Availability|
|2||Moderate Acid||2d4||1d3||70||Hard to find|
|3||Strong Acid||2d6||1d4||100||Very rare|
|2||Moderate Base||1d6+3||1d3||80||Hard to find|
|3||Strong Base||1d6+6||1d4||120||Very Rare|
All acids and bases can be counteracted by the application of buffers. Buffers are inert chemicals that have the property of neutralizing acids or bases. Each intensity of a buffer reduces the intensity of an acid or base by 1. Thus a buffer of intensity 2 would neutralize intensity 2 acids, and would reduce intensity 3 acids to intensity 1. A buffer versus acid will not function against a base (and vice versa). Buffers cost only ½ what their respective caustics cost. The effective "dose" is 12 fluid ounces.