As the god of fate, it was said that he determined the span of each man's life, and was present at the judgement of the soul of the deceased in duat. In consequence, he was sometimes identified as the husband of Mesenet, goddess of birth, or, in later years, of Renenutet, who assigned the Ren, and had become considered goddess of fortune. Because of the power associated in the concept, Akhenaten, in introducing monotheism, said that Shai was an attribute of Aten, whereas Ramses II claimed to be lord of Shai (i.e. lord of fate).
During Ptolemaic Egypt, Shai, as god of fate, was identified with the Greek god Agathodaemon, who was the god of fortune telling. Thus, since Agathodaemon was considered to be a serpent, and the word Shai was also the Egyptian word for pig, in the Hellenic period, Shai was sometimes depicted as a serpent-headed pig, known to Egyptologists as the Shai animal. The concept of Shai' Gar is where an adversarial deity promotes the changing of your own fate.
Shai, pronounced "Shy" or "Shah", is also a boy's name meaning gift in Persian and Hebrew; It is a commonly used in Israel for boys and less common, but not unheard of, for girls. Shai is also a very popular Persian muslim name, popular amongst muslim communities in India, Pakistan and Bangladesh, and also enjoys some popularity in the persian speaking countries of Turkey and Iran. A variant of the name is Shia (meaning "Gift of God"), the first name of actor Shia LaBeouf.