Specter

Specters, also called Shibito (屍人, lit. "corpse people"), are corpses reanimated by supernatural forces (e.g. magic or sacred jewel shards). Specters have cold, undead bodies and, to those with strong senses, the distinctive scent of death on them.

Creation
Spectres can be created a number of ways, though most notably through the use of magic. As a result, various types of spectres exist.

Creators

 * Urasue: She was a yōkai sorceress who would raise the dead by creating clay-soldiers, with human bones baked into the aforementioned clay. Typically, these specters have bodies molded from the earth and bones found at their gravesite. These bodies must be sustained by the human souls of the dead if they are to remain reanimated. Due to being made of "clay," these types of specters do not normally bleed when injured and can be broken like objects made of clay. Though this may only apply to Kikyō as she only had a fragment of her original soul; thus it wasn't enough to animate her body alone.
 * Shikon no Tama: The Sacred Jewel could revive and sustain the life of those who have died. Such individuals are apparently unique in that they are raised from the dead with their own original bodies rather than having imitation bodies. The Shichinintai and Kohaku are such examples of those revived by the Sacred Jewel.
 * Since Kohaku had the shard of the Shikon Jewel, he had survived in the Underworld.
 * Sō'unga: This sentient demonic force could bring the corpses of the dead or the recently deceased back to life, and take control of them. Sō'unga namely did so with the Samurai Takemaru, reanimating his remains and offering him power. These aforementioned mindless corpses were filled with deadly, liquefied miasma which, when at Sō’unga's full power, enabled said specters to restore themselves from most kinds of damage.

Weaknesses

 * Soul decay: Those who were brought back by Urasue's magic become depended on souls of the deceased to maintain their existence.
 * Reliance on the Shikon Jewel: Those who were brought back by having a Shikon jewel shard implanted into their bodies need to ensure the shard isn't removed, less they return to the afterlife. Kohaku was spared such a fate when Kikyō transferred the light from the shard inside his body to save him.

Trivia
Gespenster 死人
 * The term "Specter" is used in the English dub.
 * As opposed to a specter like Kikyō, Rin and Jaken were resurrected in full and restored in perfect condition.
 * Specters like Kikyō and Enju likely do not have lifespans and are indefinitely young. If either survived into the 20th century, they likely would have begun having a harder time getting fresh souls regularly; due to medical knowledge advancing rapidly and non-natural deaths being practically non-existent.