The oral tradition gives an origin to the goddess Tara. The legend begins with the churning of the ocean between the Devas and Asuras. Lord Shiva drank the poison (Halahala) that was created from the churning of the ocean (in the process turning his throat blue and earning him the epithet Nilakantha), thus saving the world from destruction, but fell unconscious under its powerful effect. Tara Ma appeared and took Shiva on her lap. She suckled him, the milk from her breasts counteracting the poison, and he recovered. This story is reminiscent of the one in which Shiva stops the rampaging Kali by becoming an infant. Seeing the child, Kali's maternal instinct comes to the fore and when she was feeding him her breast milk Shiva sucked her rage out while sucking the milk. In both cases, Shiva assumes the position of an infant vis-à-vis the Goddess. Mainly Tara is a form of Durga or Parvati. As Per Shakti Mahabhagwat, She is the one who created 1st Seed from which the entire universe took birth in the form of Lord Vishnu. Since he was Non manifested divinity so next Mahavidya expanded him so that manifested divinity Lord Brahma took birth from him.
Kali and Tara are similar in appearance. They both are described as standing upon a supine Shiva in an inert or corpse-like form. However, while Kali is described as black, Tara is described as blue. Both wear minimal clothing, however Tara wears a tiger-skin skirt, while Kali wears only a girdle of severed human arms. Both wear a necklace of severed human heads and the previously mentioned girdle of arms. Both have a lolling tongue, and blood oozes from their mouths. Their appearances are so strikingly similar that it is easy to mistake one for the other. Indeed, they are often said to be manifestations of each other; for example, in their thousand-name hymns they share many epithets as well as having each other's names. Tara, for example, is called Kalika, Ugra-kali, Mahakali, and Bhadra-kali. Tara is said to be more approachable to the devotee (Bhakta) or Tantrika because of her maternal instincts; however a large population of Bengali Hindus approach Kali herself as "Ma" or "mother".
Like Kali, furthermore, Tara in her Hindu context enjoys blood. In her hymn of a hundred names from the Mundamala-tantra, she is called "She Who Likes Blood", "She Who Is Smeared with Blood" and "She Who Enjoys Blood Sacrifice". The Tara-tantra describes Tara's delight in both animal and human blood but says that the latter is more pleasing to her. The blood of devotees is to be taken from specified parts of the body, such as the forehead, hands, breasts, head, or area between the eyebrows; some of these areas may correspond to the different chakras, spiritual centers within the body.
Tara can be distinguished visually from Kali primarily via her implements. Four armed, she carries a sacrificial sword, a severed head or skull cup, a lotus and scissors. Kali never holds a lotus or a pair of scissors.
Tara Yantra
Tara Mantra
Green Tara Mantra
http://en.wikipedia.org/wiki/Tara_(Devi)
