Al-Khidr, the Green One, is the deathless prophet-saint of popular Islam who guards rivers and the sea and comes to the aid of those in danger on the water. Tradition holds that he drank from the Water of Life and became immortal, and that the barren ground turns green wherever he rests. Across the Nile lands his cult attaches him firmly to the river, and in the syncretic religion of the Nubians, in which Islamic saints and Nile cults overlie the older beliefs, he stands among the benevolent guardians of the water alongside the angels of the river. He is a borrowed and pan-Islamic figure rather than a purely Nubian one, but his assimilation into the Nubian river cult is characteristic of the layering that scholars such as Kennedy have described for the region.