Steel Dragon

"I'll have you know, my scales are made of the toughest steel! You will know the wrath of Mirankho- No, Inastrelle, don't go over there! Those are dangerous mortals! Come back here, youngling!"

— Mirankhor the Eternal and his daughter Inastrelle who hasn't learned what "stranger danger" is

Born in Armour

Born with shining steel and iron scales, these dragons are incredibly durable. Their armour can withstand the mightiest blows, and the strength they can unleash is capable of rending a castle wall down in one strike.
Steel plates coat their belly, protecting their most vulnerable parts, and their iron scales sheath the rest of their body from harm. Iron spines grow along their back, down to the tip of their tail, ending in a fierce barb. Even the leather of their wings have iron in them, threading its strength throughout.
Their strength and durability is an incredible advantage, however the weight of their own body makes them one of the slowest dragon species in the Eight Lands, both on foot and in the air. Much like a boulder launched from a trebuchet, once it starts moving, one would find it impossible to stop them.

Forged in Heat

As steel dragons grow and fight, their steel becomes dull, going from a bright shine to a dull sheen.
Some equate this phenomenon to their metal becoming tempered or work-hardened. While there are some young dragons who might attempt to temper their steel in the blazing fires of other dragons, it is not an accepted practice amongst these dragons as achieving a dull sheen to their steel is seen as a trophy for gaining experience as they grow. Those who do succeed in tempering their steel prematurely are often mocked and ridiculed by other steel dragons.
Though this mockery is rarely heard by mortals, one angry steel dragon once yelled that they "weren't a bloody hotspot" when stampeding through a town.

by Theiket (via Midjourney)