Among the trinity Vishnu's status is that of the Preserver (Shiva is the destroyer and Brahma is the creator).Vishnu's significance and appearance has been described in the Puranas and Upanishads.
Vishnu is typically portrayed with a dark complexion and four hands - one holding the Sudarshan Chakra (a discus, Vishnu's primary weapon), one with a lotus (named Padma), one with a shankh (conch) and one with a gada (mace). His abode is Vaikuntha and his vehicle is Garuda (a giant eagle deity). Vishnu is frequently showed as reclining under the heads of a many headed snake, Sheshnaga (a serpent deity) on the waves of an ocean, or as standing on the waves of the ocean.
Vishnu's wife is Lakhsmi, the Goddess of wealth and fortune. The major worshippers of Vishnu are known as Vaishanavas. Vishnu has manifested himself on Earth in several avatars, in shapes of human, animal or fish in order to eradicate some great evil or to do some great good.
It is generally believed that Vishnu has already appeared in 9 avatars and the tenth is awaited. These avatars are:
Vishnu appearing in form of a fish to resurrect the Vedas immersed under water
Vishnu appearing in form of a tortoise to stabilize the trembling earth
Vishnu appearing in form of a boar to draw out the Earth from a Great Deluge using his tusks.
Vishnu appearing a half lion - half man form to kill the evil king Hiranyakashyap who could be killed by no known man or animal form, neither at day nor at night, not by fire, water or weapon, neither on Earth nor in the heavens. Thus Bhagwaan Narasimha who was neither animal nor man, killed Hiranyakashyap at evening time, using his teeth after laying him on his thigh (neither earth nor heavens).
Vishnu appearing in a dwarf form to restrain Bali who had defeated Indra dn humbled other Gods. When Vamana appeared with other Brahmanas at one of Bali's religious rituals, he offered Vamana any gift that he wanted and Vamana said he would take land covered by his three steps to which Bali happily agreed. The first two steps of Vamana covered the heavan and earth.
Vishnu appearing in a Brahmana form wielding a Parsu (an axe like weapon) to repress tyranny of corrupt kings and their ministers.
Vishnu appearing as Rama, the son of Dashrath, the king of Ayodhya, to destroy the demon Ravana.
Vishnu appearing in his most perfect avatar as Krishna, to destroy evil (including Kansa and Duryodhana)
Vishnu appearing as the elder brother of Krishna.
The yet to appear avatar of Vishnu at the end of Kaliyuga.
Vishnu: Radha, Radhe, Narayana