Temple legend · 4 tellings · Pan-India, South India
The birth of Ayyappa
Brahma's boon to Mahishi — that only a child of Vishnu and Shiva can kill her — forces Vishnu to take the Mohini form; Shiva's desire for Mohini yields a son, found and raised by the king of Pandalam, who kills Mahishi and takes his seat at Sabarimala.
The state's telling begins with Mahishi's boon from Brahma: only a child of Vishnu and Shiva can end her. So Vishnu becomes Mohini and bears a son to Shiva. King Rajasekhara of Pandalam, childless, finds the baby by the river with a bell at his neck and calls him Manikandan. When the queen, wanting the throne for her own son, pretends to be ill and demands tigress's milk, the boy goes into the forest, confronts Mahishi in the gods' realm and throws her down to earth, then comes home on a tigress. Revealing who he is, he shoots an arrow that falls on the Sabari hill, and the king raises the Dharma Sastha temple there. The account does not mention Vavar, the eighteen steps or Shabari.
What is different here:
Base telling. Official but incomplete: no Vavar, no eighteen steps, no Bhasmasura prelude.
The textual roots are separate pieces. The Bhagavata (8.12) has Shiva ask to see Mohini after the churning, chase her, and lose his seed, from which mines of precious metal arise — no child is named. The Brahmanda Purana is the text that gives their union a son, Maha-Shasta, later identified with Ayyappa; the Agni and Shiva Puranas instead have the seed produce lingas or, poured into Anjana's ear, Hanuman. Wikipedia's Mohini article gathers these; the Brahmanda passage itself was not read.
What is different here:
No Mahishi, no Pandalam; the child is Shasta rather than Ayyappa, or no child at all.
The Tamil Kanda Puranam names the child of Shiva and Mohini as Aiyanar and reads Vishnu in that form as Shiva's own power. Aiyanar is attested in Tamil inscriptions from the third and fourth centuries and in Sangam poetry, long before the Kerala cult, and shares with Ayyappa the yoga band around the knees; scholars regard him as the older Dravidian figure, and Clothey derives the name from the god of the Ay chieftains.
What is different here:
The son is the Tamil village guardian Aiyanar, not the Sabarimala god; Vishnu-as-Mohini is glossed as Shiva's shakti.
Popular Sabarimala telling with the Bhasmasura prelude
South India · KeralaFolk
Popular pilgrimage tellings join two stories: after Mohini has danced Bhasmasura to his death, Shiva asks to see that form again, pursues and embraces her, and Ayyappa is conceived. Pattanaik adds that the child is born without a womb (ayonija) and is therefore Hara-Hari-suta, the son of two gods, and reads Sabarimala as a meeting point of tribal, folk, Shakta, Vaishnava, Shaiva and Muslim strands — attribute that to him. Vavar, Ayyappa's companion honoured at Erumeli, is variously a robber turned lieutenant or a Muslim saint.
What is different here:
Adds the Bhasmasura episode as the occasion and Vavar as companion; Pattanaik's interpretive frame is his own.