Abd Allah ibn Saba
Abd Allah ibn Saba is considered the first ghulat (extremist). He was the first one to declare faith in the Imamate of Ali. After Ali’s death, he is said to maintain this idea that "a devil in ʿAli’s appearance had been murdered" and ʿAli had ascended to heaven and that his occultation (rajʿa) was imminent. Saba probably invented the concept of ghayba and return.