Groyne is a dragon belonging to Dr. Bergstrom. When first introduced in the beginning of Icefire, he is in the shape of a narwhal tusk, and Bergstrom claims he is an 'Inuit talisman'. When David Rain shakes the bone in his fist, he is granted an image - his dragon Gadzooks writing the word Lorel on his pad. He was also responsible for Gretel's release from her cage in "Fire Star", chapter 9.
In dragon form, Groyne is described as pure-white and birdlike. He can travel anywhere, turn invisible and imitate other clay dragons.
In The Fire Eternal he appears to become a dragon belonging to David, as he is among the four that go to David through the 'fairy door', though it is not certain that Dr.Bergstrom has 'given him up'. Groyne is a very special dragon who can shape-shift, teleport whoever is holding him (best done in the shape of a narwhal's tusk) and become invisible.
In Dark Fire Joseph Henry steals Groyne's powers along with several other Pennykettle dragons in the form of Gwillan.
In Fire World Angel gives him back to David. He appears once in The Fire Ascending when Gwilanna threw him at a rock he turned into Groyne