A Gust-Caller is seen as a slender, spinning column of air, almost invisible, made visible by what it carries: dust, snow, torn cloud. At its top is a brighter, pale-blue knot that turns towards whatever it watches. When it calls a gust, it draws in breath like a bellows, the air around it falls silent, and then the wind comes, with a roar like a waterfall. It smells of snow.

They hover among the floating islands and along the wind-roads of the Unbound Gale.

A Gust-Caller decides who passes. It clears a road for those it favours with a following wind, and blocks those it opposes with a wall of air. What makes it favour one traveller over another is not known; travellers say boldness helps, and hesitation does not.

It summons winds strong enough to hurl a traveller across the sky or hold them still against their will.

A traveller it favours crosses the Gale in moments. Their danger is a wind that sends a traveller where they did not mean to go.

Sailors on Caeldon whistle for a wind, and some say they whistle to the caller of gusts; travellers' tales of the Gust-Callers may lie behind the habit.

Wreckers on the outer coasts are said to whistle the other way, for a gale onto the rocks, and sailors who catch a man whistling ashore on a storm night throw him off the quay.