Thunderbird

Thunderbirds are enormous birds who live high up in the Devil's Teeth Range as well as on small islands across The Brightwater. They can be easily identified by their large wingspan, which has been known to extend to approximately 50m, and by their striking feathers. No Thunderbird appears the same, with mottled feather colours of reds, yellows, blues, and greens. Additionally, they are unique in the fact that they possess 4 wings - with 2 large ones used for gliding and 2 smaller ones immediately behind them which are believed to be used for control.
The biological details of Thunderbirds are a mystery as, despite their large frames, they have not been observed to eat, sleep, or mate. The rare observations of them have always been during flight, leading some to specilate that they may behave similarly to Birds-of-Prey, where they glide over extremely large distances. For food, it has been suggested that the ones living in the Devil's Teeth Range likely subscide mostly on large beasts such as Devilbacks, while those on the Brightwater likely eat Black Whales and other large fish.
Many myths say that Thunderbirds are the source of many weather systems (including The Maw), which they create by flapping their massive wings.

"Their cries turn into lightning and their wing beats into thunder. Their turns become tornadoes, to break the ships asunder. It's talons are the winters chill which will leave your courage hollow. Beware, beware the Thunderbird, and the storm that surely follows."

A Thunderbird Calling, from Scenes of the Summer Shores, by Amose Bouchard