Shyena (Hinduism)
Shyena (Sanskrit: श्येन ) is the divine hawk identified with Agni, who ascends to heaven for bringing soma (nectar) to earth with the intention of rejuvenating and revitalizing of all things that exist on earth. It also refers to the fire-altar constructed with bricks (Agni Chayana) in the shape of a hawk (symbolizing the essence of Agni) in the Vedic ritual. The Yajurveda prescribes prayers and mantras meant to be recited during the course of the construction of this fire-altar which represents the creator and the created. In the Puranas, Shyena becomes Garuda, the vehicle of Lord  Vishnu, which finds mention also in the Adi Parva of the Mahabharata, and who brought amrita from heaven at the behest of Kadru, the mother of serpents and a co-wife of Rishi Kasyapa. Shyena and Suparna, both, refer to the eagle and the falcon (hawk), two of the swiftest birds (of prey). In the Rig Veda mantra (I.164.20) - द्वा सुपर्णा सयुजा सखाया समानं वृक्षं परि षस्वजाते – there is in fact a reference to these two types of suparnas which are identified as the golden oriole, having beautiful wings, and the eagle. In a mantra addressed to the Vedic god  Indra, Rishi Vamadeva refers to Shyena as the suparna which brings soma, the favorite oblation of the gods. In the Rig Veda, this term is also used to denote a horse. Shyena, along with Ketu Agneya and Vatsa, is one of the sons of Agni, who are all rishis. Shyena denotes the Atman, to it belongs the power of realizing the Sole Reality. Shyena is referred to as a malevolent sacrifice (yajna) conducted with the intention of causing harm to others. At the commencement of the Kurukshetra War which lasted for eighteen days, the Pandavas, being aware that Bhishma stood  protected by the "makara vyuha" and was ready for battle, they had adopted the invincible "sheyna vyuha" with Bhima leading stationed at the mouth and Arjuna stationed at the neck of the bird-shaped vyuha, and Yudhishthira patrolling the rear.