Wraith

Wraiths (死霊) are low-tier undead.

Appearance
A Wraith resembles a black ghost with a wailing expression. There seems to be a difference of appearances of Wraiths in the New World and those from YGGDRASIL. Normally the visuals of Wraiths in the game portrayed them as human-like ghosts. However in the New World, Ainz's experiment has revealed that that the Wraith's appearance will depend specifically on the eye of the beholder. For example, a Wraith to a human the would appear as a human ghost, whereas a goblin would see a goblin ghost.

Abilities
Wraiths specialize in stealth, using it in both offense and defense. Wraiths have astral bodies, and so they could move straight through walls and other such obstacles as well as fly. Still, there was a limit depending on how thick those walls were, so it was hardly unlimited, but the thickness of normal room’s walls were no problem for it.

In addition to that, wraiths even possess the ability to life-steal their foes.

Based on the Web Novel, they might be the ones who could pass through walls and had a specialization of hit and run tactics. In other words, the possibility is high that they can deal damage by negative touch.

Trivia

 * A Wraith was summoned by Ainz Ooal Gown during the E-Rantel Cemetery Incident while saving Nfirea Bareare, to halt any interference from other adventurers.
 * Wraith did not appear in the Anime, only in the Manga and the Light Novel.
 * According to Neia, Wraith would take on the shape of the species who saw them.
 * During the campaign to liberate the Northern Holy Kingdom, Ainz summoned several undead called High Wraiths.
 * Incorporeal Wraiths could pass through walls and were suitable for infiltration, but he could not use the spell, [Undeath Slave Sight] with them. Suzuki Satoru knew that it had been possible in the game once, but it had been patched out at some point.