The Origins of the Mahdi Imam

The 12ershis believe only in the line of 12 imams which ended in the occultation of the 12th Imam. And she have continued to await his reappearance as the Mahdi before the end of time. So where does this idea come from? And does it play a part in Esma'il's thinking? Yes. The various Shia groups and communities at one time or another have had this idea of a Mahdi imam, an imam who has gone into occultation and who would reappear in the imminent future. But that the whole idea of Mahdi's itself, it actually evolved over time.