The Tidewyrm is the great sea dragon of the Shattercoast and the Whale-Road, a creature every Skeldr sailor has heard of and few wish to meet.
Appearance
A Tidewyrm is enormous in length: when its head rises beside a longship, loops of its body still break the water far behind, crested with a row of curved, fin-like spines. Its scales are dark slate-blue, small and tightly overlapping like mail, fading to a pale, ridged, pearl-gray underside along the throat and belly. Its head is long and narrow, more eel than dragon, with a smooth snout and a calm, heavy-lidded eye. Instead of horns it carries great webbed crests like the fins of a fish, translucent and veined, sweeping back from the skull. Beneath them hangs a mane of long, pale tendrils, and before a storm the tip of each one glows a cold sea-green. Seawater pours from its jaws and crests when it rises.
It is most often seen in heavy seas off steep, snow-covered coasts, under a broken storm sky.
Behaviour
Tidewyrms migrate along ancient ocean routes and sometimes follow Skeldr fleets for days. Most attacks happen when ships lie over their breeding waters or carry strongly resonant artifacts. Like keel gnawers, they seem drawn to resonant timber.
Sailors' lore
Skeldr sailors say a Tidewyrm never forgets a ship. It learns each hull by its sound in the water, and a ship that has once been followed will be followed again, years later, by the same wyrm. Pilots watch the tendrils of a following wyrm the way farmers watch the sky: when the green light shows, they take in sail, because a storm will come within the day.
Whether a Tidewyrm that follows a ship is a curse, a test from Thor, or a protection against something worse below is an argument as old as the sea roads, and it is still carried on at every oar bench. Most ports agree on one thing: a Tidewyrm attacks only for a reason, whether a ship is lying over its breeding waters, carrying resonant cargo, or breaking the old law of the sea. When a ship is lost to one, Skeldr storytellers begin by asking what the crew had done.
Some say the Tidewyrm keeps the oldest roads of the deep together with the Lantern Leviathan.