Shai was the god who determined a person's fate and the span of his life, as well as the course of his afterlife, since he also was present at the judgement of the dead in the hereafter. His name means "he who determines".
Shai is related to several other gods and goddesses. He is sometimes mentioned as the husband of Meskhenet, the personification of the birth brick (the brick on which babies were delivered) and thus the goddess of childbirth, who also determined fate.
Another goddess with whom Shai was associated was Renenutet, the goddess of harvest. Both can be mentioned together and even were considered to be the names of other gods.
Shai could even be a form of the creator and sun god, as he is called "he who is in Nun".
In Ptolemaic times Shai was also connected to Agathodaemon, a Greek god whose name Agathos Daimon (or Agathodaemon) meant "Good spirit"; he was the bringing good luck and health and was the companion of Tyche Agathe ("Good Fortune").