Ferrous Dragon
Ferrous Dragons are a lesser family of dragon in Dungeons & Dragons. Introduced in an article for Advanced Dungeons & Dragons in Dragon Magazine #170, they are a branch off of the Metallic Dragon tree, defined by both their deriving from "baser" metals and their strong adherence to the Lawful alignment instead of the Goodly alignments.
The demigod-like ruler of the Ferrous Dragons is Gruaghlothor.
Ferrous Dragons were later updated for 3rd edition in issue #356 of Dragon Magazine. Aside from the lack of any mention of Gruaghlothor, they remained pretty much identical to their AD&D selves.
The Cobalt and Iron Dragons would later be promoted to full-fledged members of the Metallic Dragons in D&D 4th edition. Check the Metallics page for info on the 4e rendition of those dragons.