The term Da'i al-Mutlaq literally meaning 'the absolute, or unrestricted, missionary', is the most senior spiritual rank and office in Tayyibi Isma'ilism. The Da'i al-Mutlaq has headed the Tayyibi community since the seclusion of the 21st Tayyibi Imam, at-Tayyib Abu'l-Qasim, traditionally placed in 528 AH/1134 AD.

Occultation in Shia Islam refers to the eschatological belief that the Mahdi, a descendant of the Islamic prophet Muhammad, has already been born and he was subsequently concealed, but he will reemerge and he will establish justice and peace on earth at the end of time. The signs of his (re)appearance are largely common in Shia and Sunni, , and the belief in the eschatological Mahdi remains popular among all Muslims, possibly owing to numerous traditions to this effect in canonical Sunni and Shia sources.