The bubun are undead, created from the corpses of humans by the Hand of the Dead who control them. They are the spiritless husks of a person, and during their seven-year lifespan of servitude labor mindlessly at simple tasks. They are tireless and reliable soldiers if not the most competent, and are used by the Hand as the massive ground forces of their formidable armies. The connection between body and spirit is temporarily severed, and the body is instead animated with a more general animating force or vitality, allowing it to obey simple commands that allow it to walk, use tools, fight, and serve any number of other basic labour tasks, as instructed by a Hand that controls it. It cannot speak, acquire new memories, or use the skills or abilities it had in life - it is a shell. The bubun came into existence at the time of the Corps, first in small numbers but later in much larger quantities. To be rendered bubun, a body must be largely intact. The lifespan of a bubun is around seven years - at that time, whatever animating force was in it fades, and its spirit is permitted to rejoin the body as it becomes an ancestor, remembering nothing of its time as a bubun. The main sources of corpses are enemies slain in battle, executed criminals, and the poor. Impoverished families frequently will allow a family member to be rendered bubun in exchange for payment, a form of rental of the body that defers its time as an ancestor for a seven-year term. When bubuns are held thus in trust, it is typical for a member of the family to wear a bustul, an inscribed clay tablet on a chain, which acts both as a measure of security of the identity of the deceased but also a public promise to care for their ancestor upon their return, a symbol of the sacrifice they have made. Bubuns are about 2-3% of the population in most regions of the former Empire, but in Hasmala as many as 10% of the population at any time are rendered bubun. Bubun are not people, are not sentient, and are not subject to the same laws against murder, assault, etc., as any ordinary person (or revenant) would be. However, the total destruction (e.g., by fire) or loss of a bubun's body is considered a matter of concern, and in the case of bubun who have known descendants or other lineal kin, a matter that may be remedied by heavy fines.
A bubun appears as a walking corpse. It does not decay, is not bloody or otherwise falling apart. However, it is cold to the touch, and pale (no flowing blood). All bubun walk with almost the same, just slightly abnormal gait - as opposed to living humans who usually have their own distinct posture and gait during life. No one would mistake a bubun for a human except in poor visibility. They do not make vocal noises and do not breathe. Bubun who experience serious injuries that would limit their mobility are normally decommissioned and returned to their relatives. Bubun who die in ways that would not affect their body permanently are simply reanimated.
In battle, bubun are incapable of strategy other than that imparted to them directly by their commanding Hand, and possess neither cunning nor a self-preservation instinct. Some Hands specialize in using bubun in battle - they serve well as a distraction, as an obstacle, and even sometimes as the target for certain spells. A Hand does have an obligation to minimize the chance that a bubun's body will be lost entirely, but otherwise is perfectly theologically and ethically entitled to use them as necessary.
The effect of large numbers of bubun on the economy and social inequality is considerable, especially when and where they exist in large numbers. Bubun serve many functions that would otherwise be occupied by the poorest of the poor in many communities, with the social expectation being that the Hand, who profit enormously from their agricultural and other labour, will redistribute wealth. At times of shortages of bubun, punishments in criminal justice often become more severe, with capital punishment (using forms that do not affect the body) being widely used. In communities with large numbers of corpseborn and large numbers of bubun, the labour of bubun is preferred - they may be dead, but at least they are not stigmatized. Wealthy households will often employ a Hand who acts as a sort of steward, and then rent bubun for various functions within the household and its lands.