Lord Vishnu is regarded as one of the primary forms of gods among the Trimurti. Vishnu is described as having dark complexion of water filled clouds and as having four arms. He is often depicted as resting on the serpent named Shesha. Shesha is said to hold all the planets of the universe on his hoods and to constantly sing the glories of lord Vishnu from all his mouths.
Vishnu as supreme lord who created unlimited universes and enter each of them as Lord of the Universe. Vishnu's vehicle or vãhana is the Garuda, the eagle.
Before there was creation, there was Vishnu asleep and floating in a vast sea of nothingness. Upon waking and stirring, a lotus sprang from his belly and blossomed, giving birth to Brahma. Brahma then set out to create the entire universe.
Vishnu has 10 main incarnations known as Dashavatara: Rama, Krishna, Buddha, Vamana, Narsimha, Varaha, Kurma, Matsya, Parashuram and kalki. Lord Vishnu took the form of a beautiful women named 'Mohini' to take back the Amrit from demons.
Vishnu would constantly come down to earth in the form of Lord Narayana in order to deliver messages or to make sure things are going according to the Divine plan.
As Lord Vishnu has four hands, each hand hold an object that emphasize something. A conch she'll or shankha named Panchajanya, is held in the upper left hand. It represents the power of lord Vishnu to create and maintain the universe. The chakra, a sharp, spinning, discus like weapon named Sudarshana is held by the upper right hand. The chakra represents the destruction of ego in the awakening and realization of the souls original nature.
A crown adorns his head. The crown symbolizes his supreme authority. The crown sometimes include the peacock feather borrowing from his Krishna avatar.
The typical blue colour of Vishnu is a symbol of his purity and his eternal nature. Vishnu is the preservation aspect of the universe. The shreevatsa mark is on his chest, symbolizing his consort Lakshmi. He wears he auspacious Kaustubh jewel around his neck and a Garland of flowers (vanamala). Lakshmi dwells in this jewel on vishnu's chest.
Om namo bhagwate Vasudevaya..
means
I no to the lord who lives in the heart of all..
As Vishnu is the preserver and the supreme God, whenever there is decline in human values, morals and religion wickedness reaches at it's peak, Vishnu takes human form and resources back to exquisite.