Firewyrm

Firewyrms are possibly akin to dragons, are creatures that breath fire but have no wings and bore through rock, soil and stone. The young are no larger than a child’s arm, while the largest can grow to immense sizes. They were encountered by slaves of the Valyrian Freehold in the mines of the Fourteen Fires. According to old tales, the firewyrms were in the Fourteen Fires long before the dragons came. They have no love for men.