Iron Dragon

Iron dragons were intelligent and deadly dragons that preferred to subdue rather than kill intruders. They were the most powerful of the ferrous dragons.
Iron dragons were a larger variety of dragon, with wyrmlings being at least 9 feet (2.7 meters) long and great wyrms being as much as 289 feet (88.1 meters) long (body length 163 ft (49.7 m), tail length 126 ft (38.4 m)). They had broad, almost shovel-shaped heads with multiple thick, backwards-pointing horns, and large plates that resembled shark fins ran down their spine. Their scales were a glossy, metallic black that, after adulthood, began to take on silver highlights; great wyrm scales looked like moonlight on a dark, rippling pool.
Personality Iron dragons, like all of the ferrous dragons, were lawful in nature, adhering to a strict hierarchy. Like the other ferrous dragons, they were determined to reclaim their group's prestige, which was lost after a long and bloody war amongst their kind.
Abilities Iron dragons possessed many different abilities common to the true dragons, such as darkvision and blindsense. They could assume an alternate form, that of an average-sized animal or humanoid, three times each day. Great wyrm iron dragons could, once each day, turn creatures to iron in a manner similar to the flesh to stone spell.
Iron dragons also had innate spell-like abilities. By the time they were at least young they could replicate heat metal three times each day, juveniles gained stone shape twice each day, by adulthood they could replicate detect thoughts twice each day, ancients could replicate transmute rock to mud twice each day, and old ones could replicate wall of iron twice each day.
Additionally, iron dragons were known to have two different breath weapons: a cloud of sleep gas, and a 90 feet (27 meters) cone of electrical sparks. The cloud of sleep gas was typically measured at 50 feet (15 meters) long, 40 feet (12 meters) wide, and 30 feet (9.1 meters) high, while the sparks formed a cone about 5 feet (1.5 meters) wide at the dragon's mouth and 30 feet (9.1 meters) in diameter at the far end.
Like all ferrous dragons, iron dragons also possessed metalsense, a peculiar ability that allowed them to sense both the location and amount of any non-precious metal within at least 30 feet (9.1 meters) of them (as wyrmlings; great wyrms could sense it up to 360 ft (110 m) away). This proved a great hinderance for anyone trying to sneak up on them while carrying any weapons or armor made of steel or other non-precious metals.
Combat Iron dragons were far more interested in acquiring information than in fighting, and preferred to use diplomacy or intimidation to avoid combat if possible. If they were drawn or forced into battle, they preferred to subdue or incapacitate opponents, either with spells, spell-like abilities, or their sleep-inducing breathe weapon, before questioning them for information. However, they usually ate enemies after learning everything they could; although iron dragons were not completely merciless, they always expected some form of payment in return for such kindness.
Society Iron dragons, like the other ferrous dragons, were arranged into family groups, two or three of which made up a clan; clans were ruled by the oldest and/or most powerful member of the clan. There were several clans of iron dragons, each with a specific place in the hierarchy of the iron dragons. The iron dragons as a whole were ruled by a sovereign great wyrm to whom the clan leaders reported to directly; this sovereign in turn answered to the Supreme Dragon of the ferrous dragons, Gruaghlothor. Some accounts claimed that the sovereign had a telepathic link with each clan leader, and that Gruaghlothor had a telepathic link with the sovereign. In the overall hierarchy of the ferrous dragons, the iron dragons were the highest ranking, although they did not officially have any authority over the other four types.
Iron dragons loathed red dragons, who they saw as a stain upon the reputation of all dragonkind; the red dragons in turn hated the iron dragons just as much and viewed them as pathetic intruders. Iron dragons were also known to come into conflict with dwarves and other peoples that mined iron ore.