Planeblood

Planeblood was a special alloy made during the creation of the world by the commingling of the essences of the three great progenitor wyrms Siberys, Eberron, and Khyber. The natural aversion that Siberys and Khyber felt from the dawn of time was infused into the substance, creating the potential for great bursts of arcane power; the calming presence of Eberron and the strength of the magics that created the metal were what made this union possible.

Physically planeblood looks much like obsidian—it has the same telltale sheen—but there are streams of dark blue and crimson that swim throughout its dark depths. Sanctified planeblood replaces the black colour with deep gold, but its powers remain the same.

Abilities
Items forged from planeblood are extraordinarily light, weighing only three-quarters as much as similar items crafted from iron. They also grant considerable powers when wielded against extraplanar foes. Weapons and armour forged from planeblood are always of masterwork quality.

Weapons

Weapons crafted from planeblood confer an additional +1 to attack and damage rolls made against extraplanar creatures, but native outsiders are not subject to this bonus damage. Extraplanar creatures struck by a critical hit from a planeblood weapon must also make a Will save (DC 10 + half of the wielder's character level + the wielder's Wisdom modifier) or be banished to their home plane for 1 hour; extraplanar creatures usually not subject to extra damage from critical hits, such as elementals, are still subject to the banishing effect. Armour

Armour crafted form planeblood confers an additional +1 to Armor Class and saves made against the attacks of extraplanar creatures; this bonus does not extend to attacks made by native outsiders. Thanks to its light weight, all planeblood armour possesses a maximum Dexterity bonus 1 point higher than normal and an armor check penalty two points lower than normal, and it is considered one category lighter: that is, heavy planeblood armour is considered medium, and medium is considered light.