Ming (命) is a complicated word with a long folk and technical history, basically meaning "life" or "the balance of fate or destiny", personified as Siming.
Siming has the power to balance or unbalance yin and yang, and thus to lengthen or shorten human lifespans, or to provide health or prolong illness.
Also known as the sanshi (三尸 "Three Corpses") or sanchong (三蟲 "Three Worms"), the Three Deathbringers are part of a Daoist physiological belief that demonic creatures live inside the human body, and they seek to hasten the death of their hosts.
These three supernatural parasites allegedly enter the person at birth, and reside in the three dantian "energy centers" (head, chest, and abdomen).
Based on these reports, and perhaps other information, Siming alters the fine yin-yang balance of each individual, thus regulating each one's health or sickness, and ultimately each's lifespan.
One of the early literary references to Siming as a deity is in a section of the book Zhuangzi, from about 300 BCE (莊子, 至樂: Zhuāngzǐ, Zhì lè).
Zhuangzi retorted that he could petition Siming to use his or her powers over Fate and Destiny to restore the skull to be again a living human being, and then he or she could return to both hometown and family.
The skull emphatically denies any such desire, and ends the encounter by rhetorically asking why anyone in such a state of unassailable happiness as experienced by the dead would ever wish give this up in exchange for suffering the vicissitudes of the living?
The stars traditional names are: Shangjiang (上將), Cijiang (次將), Guixiang (貴相), Siming (司命), Sizhong (司中), and Silu (司祿).
Wenchang Wang is often depicted as an elderly scholar accompanied by two attendants, Tianlong (天聾 or Heaven-Deaf) and Diya (地啞 or Earth-Mute).