Ayyappan is a deity worshipped above all at the hill shrine of Sabarimala in Kerala, in southern India, and his parentage is unlike that of any other major Hindu god: he is held to be the son of Shiva and of Vishnu in the female form of Mohini, and is accordingly called Hariharaputra, the son of Hari (Vishnu) and Hara (Shiva). He is worshipped as a celibate deity, shown seated in a yogic posture with a band around his knees.
The pilgrimage to Sabarimala is one of the largest annual gatherings of devotees in the world. Those who undertake it traditionally keep a vow of some forty-one days beforehand, abstaining, wearing dark clothing, and living simply, and carry the irumudi, a cloth bundle of offerings, up through the forest to the shrine, addressing one another as Swami in recognition of the god within each pilgrim. The tradition of the shrine has historically restricted the entry of women of menstruating age, a practice connected to the deity's celibate character; this restriction became the subject of a widely reported legal and public debate in India in recent years. Ayyappan's worship, strongest in Kerala and the neighbouring states, has grown markedly in recent decades and draws pilgrims across lines of caste and community.