A metalborn is a feruchemist or allomancer.[1] By Wax's day, the bloodlines have been diluted, making metalborn rare.[2] All allomancers are Mistings, possessing only a single allomantic power and able to use only one metal. Likewise, a feruchemist is able to use only one metal.
Metalborn may flaunt their abilities or choose to keep them secret.[3]
A metalborn with both allomancy and feruchemy is known as a twinborn.[4]