Nila Devi

Nila Devi (or Neela Devi) is the third consort of Lord Vishnu, the other two being Sri Devi and Bhu Devi. In Paramapadam (Sri Vaikuntham) Sri Devi is seated to the right of the Lord, and Bhu Devi and Nila Devi to His left. The Veda sings the glory of Goddess Nila in Nila Suktam.

Nappinnai

What Bhu Devi (Bhūmi devi, Goddess of earth) is to Varahavatara and Sri devi (Sita) to Ramavatara, is Neela devi to Krishnavatara. Neela devi took avatar as Nappinnai, daughter of Kumbagan (brother of Yashoda) and Krishna won Her hand after conquering the seven ferocious bulls of Her father. Nappinnai's brother is Sudama. Sri Parasara Bhattar describes Krishna, intoxicated by Her beauty, as "Neela thunga sthana giri thati suptham". Nappinnai – Krishna cult is mainly limited to the Tamil speaking world.

Andal (one of the Alvars) wanted to perform devotion to her Lord Krishna like Gopikas did in Dwaparayuga. She in her Thiruppavai, wakes up Nappinai before waking up Lord Krishna. As per Srivaishnavism, saranagati (complete surrender to the Lord) is performed through His consort and in Sri Krishnaavatharam specifically it is performed through Nappinai.

Velukkudi Swamy, a proponent of Vishishtadvaita Philosophy says that Andal, singing Nachiar Tirumozhi as the daughter of Periyalvar, mentions about Rukmini. But singing as a Gopika in Thiruppavai she mentions only Nappinnai. Alvar mentions the three nachiars (consorts) as Pon mangai(Sri devi), nila mangai (Bhudevi) and pula mangai (Neela Devi) the consort of senses. It is Neela devi who keeps Bhagavan under control by her bhogam. Swami Vedanta Desika says in Daya satakam - "nisAmayatu mAm nIla yat bhOga patalai: druvam". Lord Krishna was a kshatriya by birth, thus he married Rukmini according to that. He was brought up as a vaisya (gopa), hence he married Nappinnai according to that. Neela suuktam also says - ghruNAhi - ghrutavai - payasvati etc., mentioning the characteristics of a gopika.

The name Nappinnai is found in Divya Prabandha of Alvars and Silappadikaram.