Most magic weapons and armor gain their enhancements from potent eldritch runes etched into them. These runes allow for in-depth customization of items.

Runes must be physically engraved on items through a special process to convey their effects. They take two forms: fundamental runes and property runes. Fundamental runes offer the most basic and essential benefits: a weapon potency rune adds a bonus to a weapon's attack rolls, and the striking rune adds extra weapon damage dice. An armor potency rune increases the armor's item bonus to AC, and the resilient rune grants a bonus to the wearer's saving throws. A reinforcing rune increases a shield's durability. Property runes, by contrast, grant more varied effects—typically powers that take effect each time the weapon is used or that are constant while the armor is worn, such as a rune that grants energy resistance or one that adds fire damage to a weapon's attacks.

The number of property runes a weapon or armor can have is equal to the value of its potency rune. A +1 weapon can have one property rune, but it could hold another if the +1 weapon potency rune were upgraded to a +2 weapon potency rune. Since the striking and resilient runes are fundamental runes, they don't count against this limit. A shield can't have property runes, only a reinforcing rune.

An item with runes is typically referred to by the value of its potency rune, followed by any other fundamental runes, then the names of any property runes, and ends with the name of the base item. For example, you might have a +1 longsword or +2 greater resilient fire-resistant chain mail.

Rune-etched items have the same Bulk and general characteristics as the non-magical version unless noted otherwise. The level of an item with runes etched onto it is equal to the highest level among the base item and all runes etched on it; therefore, a +1 striking mace (a 4th-level item) with a frost rune (an 8th-level rune) would be an 8th-level item.

Each rune can be etched into a specific type of armor, shield, or weapon, as indicated in the Usage entry of the rune's stat block. Explorer's clothing can have armor runes etched on it even though it's not armor, but because it's not in the light, medium, or heavy armor category, it can't have runes requiring any of those categories.

Fundamental Runes

Fundamental Rune	Etched Onto	Benefit
Armor potency	Armor	Increase item bonus to AC and determine maximum number of property runes
Resilient	Armor	Grant item bonus to saves
Reinforcing	Shield	Increase Hardness, HP, and BT
Weapon potency	Weapon	Grant an item bonus to attack rolls and determine maximum number of property runes
Striking	Weapon	Increase weapon damage dice

Table 11-6: Armor Upgrade Prices

Starting Armor	Improved Armor	Price and Process
+1 armor	+1 resilient armor	340 gp to etch resilient (8th level)
+1 resilient armor	+2 resilient armor	900 gp to etch +2 armor potency (11th level)
+2 resilient armor	+2 greater resilient armor	3,100 gp to etch greater resilient (14th level)
+2 greater resilient armor	+3 greater resilient armor	19,500 gp to etch +3 armor potency (18th level)
+3 greater resilient armor	+3 major resilient armor	46,000 gp to etch major resilient (20th level)

Table 11-7: Weapon Upgrade Prices

Starting Weapon	Improved Weapon	Price and Process
+1 weapon	+1 striking weapon	65 gp to etch striking (4th level)
+1 striking weapon	+2 striking weapon	900 gp to etch +2 weapon potency (10th level)
+2 striking weapon	+2 greater striking weapon	1,000 gp to etch greater striking (12th level)
+2 greater striking weapon	+3 greater striking weapon	8,000 gp to etch +3 weapon potency (16th level)
+3 greater striking weapon	+3 major striking weapon	30,000 gp to etch major striking (19th level)

Suits of armor can be crafted from precious materials or infused with magic to grant them abilities exceeding those of typical armor. Many suits of magic armor are created by etching runes onto them. The magic armor stat block lists the Price and attributes of the most common armors you can make with fundamental runes. Other special suits of armor might be made of precious materials, and some are specially crafted items all on their own.

Though shields can't be etched with weapon or armor runes, they can be improved by a specific type of fundamental rune known as a reinforcing rune. Reinforcing runes can be etched only on shields, including specific shields, and every reinforcing rune includes maximum Hardness and Hit Point values. Since the runes work by increasing the structural integrity of a shield by a certain amount, they can't increase the durability of a shield beyond a listed maximum value. Shields can't be etched with property runes, only reinforcing runes.

All magic shields are specific items with a wide variety of protective effects, as described in their entries.

Weapons can be crafted from precious materials or infused with magic to grant them powerful and unusual abilities.