Complex sentence: Amrita features in the "ocean-churning" Samudra manthan legend, which describes how the devas, because of a curse from the sage Durvasa, begin to lose their immortality.
Split into simpler sentences: Amrita features in the "ocean-churning" Samudra manthan legend. It describes how the devas, because of a curse from the sage Durvasa, begin to lose their immortality.