Githzerai armoursmiths in the Ever-Changing Chaos of Limbo have found a way to alloy ordinary iron with some of the shifting chaos-stuff of their native plane. The resulting metal, called entropium, is heavier than iron but can be used to make effective armour. A suit of entropium armour actually shifts as its wearer moves, allowing incredible flexibility at the cost of increased weight. Light entropium armour is considered medium and weighs 2 pounds more than normal, medium armour is heavy and weighs 5 pounds more than normal, and heavy armour is simply more so, weighing 10 pounds more than normal. Shields also weigh 2 pounds more than their steel counterparts. The armour check penalty of the armour increases by 2 for Strength-related skills (Climb and Jump) and decreases by 2 for Dexterity-related skills (Balance, Escape Artist, Hide, Move Silently, Sleight of Hand and Tumble). The arcane spell failure chance decreases by 10% (to a minimum of 5%), and the maximum Dexterity bonus increases by +2. Naturally, entropium improves only armours made primarily of metal, including chain shirts, all medium armours except hide, all heavy armours and steel shields.
Entropium has a hardness of 15 and 40 hit points per inch of thickness.
| Type of Entropium Item | Item Cost Modifier |
|---|---|
| Shield | +750 gp |
| Light Armour | +750 gp |
| Medium Armour | +2,000 gp |
| Heavy Armour | +8,000 gp |
Source: Arms and Equipment Guide (Page 20)