Naethryn.

That is its being, but not its name. It is a creature of the naether, that vast and empty void.

It glides up to one of those rare places where its existence overlaps into the world of substance. Few know of these moiety points. But they exist. Just as the sea rides up onto a rocky shore, so do the tides of the naether roll against the world above.

The naethryn finds a hidden estuary, an opening where its world and the upper world blend and shift. Rising, it swims up a choked channel, silty with substance, into the world above.

Abandoning the naether far below, it enters the depths of a black sea, birthing into the icy waters. Light never reaches these depths. Here is eternal darkness, blurring where one world ends and another begins. But the naethryn knows its way. It’s been told, instructed, willed.

The shadow creature rises through the cold, dark sea. It shudders and gains form, drawing bits of luminescent life from the ocean. The deaths are small, but they thrum through its being, vibrations of pleasure. It sails upward. More and more life is drawn. Substance builds, layer by layer, like barnacles on a ship’s keel.

Form and shape bloom out of nothingness.

Pressure lifts as aquamarine moonlight bleeds down, bathing the naether creature’s new form. As it nears the surface, schooled fish flee in clouds of scale. Even a monstrous rill shark flicks its muscular tail and vanishes.

Unconcerned, it allows them to escape. It has all the structure it needs for this world. It tests its black limbs, its long snaking tail, and swims upward out of the dark womb.

At last, the naethryn breaks the waves with a crested head and breathes the night’s salt-soaked air, testing its lungs. Lidless eyes shine with a light that does not belong to this world. It stares across the foam-limned waves toward the distant shore.

Islands breach the waves: shoals, reefs, atolls, volcanic peaks.

An archipelago.

The Summering Isles.

A hiss escapes the broken fish bones that make up its teeth. It swims toward its destination, the largest island of the archipelago. Eyes reflect the flickering lights that sparkle from the isle’s crowned peak and spill down its slopes to the sea, describing homes, streets, and ramparts. A few lamps even skip out into the waters, marking moored fishercraft and masted deepwhalers.

The naethryn ignores all, knowing its purpose.

As it crosses the ring of reefs, none note its undulating passage. Even the lesser moon hides her face behind fog and cloud. The naethryn moves through the seawater as easily as through the insubstantial reality of its home.

Land rises beneath the waves. The naethryn resists touching such solidness, gliding through the shallows, remaining in water for as long as possible. But soon, force and blood and promise drive it from the waves.

Clawed feet dig into sand. Climbing upright, it balances with a long tail. Though it wears flesh and bone, edges blur with the shadows of the dark beach. It does not belong here.

It steps forward.

It must.

Water sluices from the assassin’s shoulders as it lurches forward. Steam rises from its scales. Claws drip with more than water. It moves across the sand, turning each step to molten glass behind it.

It has come here to slay.

To slay a god.