Sluagh

From Gaelic mythology comes the terrifying tale of the Sluagh, or Sluagh na marbh—the hosts of the unforgiven dead.

And no, not “host” in the dinner-party sense.

They mean an army.

An army of ghosts.

According to folklore, this fairy host is composed of the restless souls of the dead, advancing in a crescent formation—like a flock of birds—sweeping down to snatch up the unwary.

Some say the Sluagh are part of the Wild Hunt. Others place them among the Unseelie Court. Still others claim they answer to neither, moving independently and without allegiance.

They’re believed to be the souls of the wicked, the forgotten, or the unburied—rejected by both heaven and hell. Most active around Samhain (Halloween), they were also said to appear wherever there was battle, drawn to death like carrion birds.

There are a few gentler tales. In rare stories, the Sluagh rescue people stranded on sheer cliffs, carrying them safely to shore.

But let’s be honest—that’s not their reputation.

By and large, the Sluagh are considered extremely dangerous. They’re known to abduct humans, carrying them screaming through the air to distant islands. They may attack livestock and pets, but their primary purpose is far worse: stealing the souls of the dying to swell their ranks.

And some folklore isn’t convinced the victims were dying before the Sluagh arrived.

Protection, such as it is, involves keeping any west-facing windows firmly shut so the Sluagh can’t enter—though this feels like a flimsy precaution, given they’re said to attack from any direction.

In a fascinating aside, the etymology of the word sluagh traces back through Scottish Gaelic, Old Irish, Proto-Celtic, and Middle Welsh. Across these languages, the root consistently refers to a host, army, crowd, or troop of combatants. The Proto-Celtic* slougo may originally have meant “those who serve the chief.” In Scottish Gaelic, sluagh-ghairm—meaning “battle-cry”—is thought to be the origin of the modern word slogan.

In my books, the Sluagh serve as gaolers in Gehenna—the Slipworld’s version of a super-max prison. The prison itself is unsettling enough.

But the Sluagh?

They’re the reason no one ever wants to be locked up there.

You’ll have to be patient, though.

They don’t appear until book five.