What is a wraith in shadow and bone?

In the novel "Shadow and Bone" by Leigh Bardugo, a wraith is a powerful and malevolent creature that roams the Shadow Fold, a dark and dangerous expanse of darkness filled with monsters and cursed beings. Wraiths are described as having a ghostly appearance, with pale, translucent skin and glowing red eyes. They are said to feed on human flesh and souls, and possess the ability to drain their victims of their life force.

Wraiths in the Shadow Fold are created by the Darkling, the powerful and enigmatic leader of the Grisha, a group of magical soldiers in the nation of Ravka. The Darkling uses his dark powers to summon and control these creatures, using them to terrorize and control the inhabitants of the land. Wraiths are feared by all who live near the Shadow Fold, as they are known to attack travelers and villages that stray too close to the darkness.

In "Shadow and Bone," the protagonist, Alina Starkov, encounters a wraith for the first time while traveling through the Shadow Fold with the Darkling and other Grisha. The wraiths serve as a constant threat and obstacle for Alina as she navigates the treacherous landscape and battles against the forces of darkness. The wraiths' presence adds a sense of danger and urgency to the story, as Alina must find a way to harness her own hidden powers to protect herself and defeat the darkness that threatens to consume her world.