The galebound were living things of the high places before the air got into them. Birds that ride the storm-tops, beasts of the bare peaks above the tree line, the rare climber or sky-trade hand who died where the air runs too thin to breathe. In each of them, at the moment the air should have meant their end, Sulus worked its way in and stayed. What walks or drifts afterward is thin, scattered, and wrong in a way that is hard to name and easy to feel.
A living thing needs both halves of its life-force, the soul that climbs to the Astral and the shadow that sinks to Malstaris, with a spirit between them to call itself by name. In a galebound, Sulus has pushed into that set and taken the place of part of it. Where a soul or a shadow or the self should sit, there is moving air instead, and air will not do the work those threads were for. The being holds together, after a fashion. It is not held together the way the living are.
They are not undead. No necromancer reads a shadow-trace on a galebound, and no road runs down to Malstaris beneath one. They are not alive either. The element that displaced a strand answers a different master than death does, and the galebound is left in the gap between, the way a frostwalker is left there by the cold or a cinderbound by the fire. Air's version of that gap is its own. A galebound is never quite all in one place. It feels diffuse to stand near, like a person heard through a wall, and the longer it persists the thinner and harder to hold it becomes.
What makes them is also why they are rare. To fuse an element into a strand the element has to press hard, the way Yolus pressed when the World Fire's seam tore open. Air almost never presses that hard. There is no named Air leyline anywhere, and the air layer hardly ever thickens enough at the surface to fuse anything. The only place Sulus comes near to it is high in the open atmosphere, and only rarely even there: the top of a great storm, the dead air at a height where men cannot breathe, the moment a flyer is caught where the field briefly ran thick. A galebound is made only where the high air does something it almost never does. That is the whole of why there are so few.
Sky-hands tell you to be glad of how thin the high air is. Thick air kills you slow and lets you go. The few places it runs thick enough to keep you, you do not want to be kept. — a sky-trade saying, the high lanes
Like the cold-things and the cinder-things, a galebound can be broken apart, and breaking it does not lay it to rest. Its strands are compromised, half-given to an element that will not release them, and when the body comes undone those strands do not take their proper roads. Something is left over. The difference is where it goes, and the difference is the whole of the warning.
A cinderbound leaves a haunt you can find. The burning part of it settles on the threshold where the body fell, a patch of heat with no fire under it, and a village learns the spot and learns to walk around it. A galebound leaves a haunt you cannot find, because the wind takes it before it can settle anywhere. Whatever is left of the broken self scatters on the moving air and thins out across miles of it, present along the whole reach of a wind and nowhere a person could stand and point. You cannot cleanse the place it haunts, because it haunts no place. It is in the gust that worries a shutter and the draft that should not be in a sealed room and the cold breath felt on an exposed ridge with no weather to explain it. People who live high enough to know the galebound do not speak of laying them to rest. They speak of which winds to stay out of.