Cold Iron Armor

Damned hard to forge, harms outsiders readily.

Iron is a special material, with cosmic significance. Draconic astronomers say that the stars have hearts of iron--seemingly preposterous, but perhaps dragons know better--and that iron is the fundamental material of the universe. This may be so, for in its pure form, iron is inherently harmful to all extraplanar creatures. However, heat degrades this property of iron, so to retain it, the iron must be cold-forged. This requires special equipment and training, and quite understandably, is very labor-intensive.

Effect: Extraplanar creatures have disadvantage on natural and unarmed attacks against you, and contacting you causes medium internal damage per instance.