Necromancy was a high-level magic concerning the revival of the dead. The resuscitated dead had their souls seemingly return to their body. As a result, their bodies were reanimated and could function to a limited degree as they did in life. Due to being already dead, the undead were fairly resilient and unable to be "killed" by blood loss. The undead were also capable of using tools and weapons as well as their hands and teeth to attack opponents. The techniques allowed the user to control the dead as well, making them essentially slaves to the user's will.
As a drawback, the undead's decaying bodies could limit their actions and they may have felt pain. The best method to kill the undead was to completely hack up or destroy the body. Likewise, it required the constant flow of large amounts of magic power to keep the technique in effect. Also, their tactics and mental capacity could be limited and they could meander or be easily tricked. Aside from this, the corpse soldiers had sluggish movement. Similarly, when not directly controlling the undead, they could act on their own and even betray the caster. Enemy mages could also use magic to free a reanimated individual of the caster's control.
When utilizing magic tools like the Glass of Conchita, the tool's magic was used in place of the user's own, allowing even non-magic users the ability to revive a large amount of the dead. The glass' necromancy ritual involved pouring liquid from the glass upon the actual body; if attempting to revive a large amount of corpses, the liquid could be poured on the ground of the general area. After Banica Conchita became the Demon of Gluttony, only those that had died of the Gula disease could be revived. The corpse soldiers revived by this ritual had their skin become a ghostly white pallor and, in some cases, both the hair and eyes fell out.
Due to being mindless and slow-moving, the corpse soldiers were relatively easy to defeat with the use of firearms. When not reanimated by either the original Demon of Gluttony or Banica, the corpse soldiers could be spawned with variations in terms of physical attributes, with some being particularly stronger or more agile than the rest. A variant of the corpse soldier that had its own mind and was able to speak with the other undead also existed. Another notable variant was the Worldeater, an extremely large corpse soldier with a size of up to around four meters in height that were particularly difficult to defeat with bullets.