Another highly secret alchemical substance, the secret of making Flesh Hardener is closely guarded by a handful of Suel alchemist in the Scarlet Brotherhood. This substance is used to increase the sturdiness of one's skin, having the side effect of also making the skin rough and unnatural looking. There are 3 levels of hardness which can be gained in increments as follows (the increments must be done in order, from 1 to 2 to 3):
Level 1: Over the course of 1 month of treatment (requiring 10 doses of the substance) the subject gains a +1 natural armour class bonus, permanently. This treatment has the side effect of reducing the subjects hitpoints by 1point/hit die, also permanently. Creation of this level of Flesh Hardener not only costs the standard cost, but requires gorgon blood and behir scales, both quite difficult to come by.
Level 2: Over the course of 1 month of treatment (requiring 10 doses), the subject gains another +1 to their natural armour class, permanently, and suffers another --1 hitpoints / hit die, also permanently. Creation of this level of Flesh hardener, in addition to the standard cost, requires the scales of an ancient (or older) dragon and sap from a treant.
Level 3: Over the course of yet another month of treatment (requiring 10 doses), the subject gains yet another permanent +1 to their natural armour class and gains 5/+1 damage resistance. Their is, however, a 40% chance that the subject's skin will stiffen too much, result in less flexible joints and loss of manual dexterity (-1d6 to dexterity, permanently). Creation of this level of Flesh Hardener, in addition to the standard cost, requires the scales of a greater demon (obviously, said demon must have scales...) and the essence of a solar.