In the earliest yuga (era) of Sata-yuga, a king named Manu was performing severe penance for thousands of years. One day as he was performing ablutions with river water, a small fish came into his hands and just as he was about to throw the fish back into the river, the fish requested the king to save its life. Heeding its request, the king put the fish into a jar of water but the fish started growing and the jar was not big enough for it. Then the king threw it into the river, but it soon it outgrew the river and the king then threw it into Ganges and then into the ocean. The king realised that it was Lord Vishnu himself and then the lord made an appearance and made a special request to the king. It predicted that the world would come to an end by a huge flood in seven days and requested the king to build a huge boat and take the seven sages(hermits), seeds of all plants, one animal of each type and told him that he would appear as a fish to propel the boat to Mount Himavan for surviving the flood to the next yuga(eon). True to his word, after seven days the Lord appeared and the king tied the boat to the fish by using the royal serpent Vasuki and the fish took all of them to Mt Himavan and kept them there till the flood was over and in the new era, the king started procreation a for the new era.
Kurma the Tortoise
Further to Pralaya- deluge at the beginning of the present Kalpa the Gods (devas) lost their immortality due to a curse by the short-tempered sage Durvasa.The sage had once presented a garland of flowers to Indra,king of gods, who carelessly gave it away to his elephant which trampled it. The Devas approached Vishnu for help. Vishnu then asked them to churn the ocean of milk after adding medicines into the ocean. Mt Mandara could be used a the churning stick he said. He requested them to ask them help of Asuras in lifting the mountain in exchange for offer of the share of nectar of immortality that would ensue from the churning. Both the devas and the asuras churned the ocean using the serpent Vasuki as the rope. At the start, playing a Machiavellian trick, Indra, king of the gods asked the asuras for the head end of vasuki. But asuras suspecting foul play, took the head end, only to be deceived as the poison from Vasuki was slowly weakening them. But as churning was proceeding the mountain was sinking and then Lord Vishnu took the form of the tortoise KURMA and kept the mountain afloat. As soon as the bowl of amrita, the nectar of immortality was out, the asuras grabbed it. Then Lord Vishnu took the form of an apsara, a beautiful maiden, and seduced the asuras into letting her distribute the nectar and also to abide by her order of distribution. As soon as the devas were served the maiden disappeared thus totally deceiving the asuras and making them totally weak.
Varaha the Boar
A demon Hiranyaksha, had prayed for Lord Brahma and got awarded a boon that no beast nor man nor god could kill him. But somehow from the list of beasts the name of boar was missing. This proved to be his lacunae. He then started a campaign of plunder across the worlds. He pushed the world to the Pataal loka, or the under of the sea. He stole the Vedas, the holy scriptures from the Lord Brahma, while he was asleep and performed huge atrocities.To retrieve the Vedas and to save the world the Lord Vishnu assumed the role of a boar and brought out the earth from the under of the ocean, using its two tusks. It then killed Hiranyaksha and retrieved the Vedas from the asura and brought it back to the safe custody of the Lord Brahma.
Narashima giant lion-man
In NARASIMHA Avatar, Lord Vishnu incarnates himself as a semi-man,semi-lion in this world. The king of demons(asuras), Hiranyakasyapu, wanted to become immortal and wanted to remain young forever. To this end, he meditated for Lord Brahma and because of his severe penance, the gods were frightened and asked Brahma to pacify the king. Brahma was impressed by his austerity and granted him a wish. Hiranyakasyapu wished that he be killed neither by a man or beast, nor in daylight or at night and neither inside or outside a building. Having obtained the wish he considered himself the supreme God and forbade all worship of gods by anyone. But his son Prahlada, was an ardent devotee of Vishnu. This enraged Hiranyakasyapu very much. He ordered numerous ways to kill Prahlada including asking his sister Holika to sit with Prahlada in the fire. But every time Prahlada escaped unhurt. Enraged, once he asked Prahlad to show him the Lord Vishnu. Prahlad said, "He is everywhere". Further enraged, Hiranyakasyapu knocked down a pillar, and asked if Lord was present there. Lord Vishnu then emerged as a half lion, half man from the pillar, and carried him under the arch of the doorway (neither indoors nor outdoors), and the time was evening (in the twilight), neither night nor day. He then killed Hiranyakasyapu with his claws by keeping him on his thighs (neither on earth nor in the sky) thus saving the life of his devotee Prahlada.
Vamana the dwarf
BALI, the grandson of Prahlada was a very valorous and mighty asura. By his penance and might, he conquered the whole world. Indra and other gods fearing that he and the asuras would conquer all the three worlds, went to Lord Vishnu for help. Lord Vishnu was then born as a dwarf Vamana in the household of a brahman priest. He went to Bali on growing up and asked for alms. Bali was delighted to offer him anything he requested even though his royal guru warned him that it was Lord Vishnu. Vamana then requested for the amount of land that could come under his three feet. Bali gracefully agreed. Lord Vishnu then grew in size and covered the earth and heaven in two stride. And due to lack of space, he put his third leg on Bali himself and crushed Bali to the nether or the Patala loka (underground world), thus helping the Gods out.
Parasurama Rama with the axe
In PARASURAMA Avatar, Lord Vishnu incarnates himself as a brahman priest in this world. He was brought in this world to avenge all kshatriyas who had become arrogant and were suppressing the brahmans in the world. He was born with unusual physical power, and became better fighter than any Kshatriya.He was born to Jamadagni and Renuka, and belonged to the Brighu clan. Parashurama was always carrying an axe presented to him by Lord Shiva of whom he was an ardent devotee. Kartavirya a powerful king, once went to Jamadagni's home when he was out, and after a meal, stole the Kamadhenu cow, which was supposed to give endless quantity of milk. Jamadgni was enraged and he went and killed the king and brought Kamadhenu back. On hearing this the son of the king came back and killed Jamdagni. Parasurama was enraged at this and went and avenged the death of his father by killing all kshatriyas in 21 battles. His life is story of the supremacy of brahmans over the kshatriyas.
It is the most important Avatar of Vishnu. Rama represents the peak of the historic incarnations, and by him it is defined the ideal character of Indian people.He is Vishnu descended upon earth to conquer all the Indian peninsula, included Sri Lanka, under the Bharata rule. Lord Rama is one of the most adored gods in India. He is always holding a bow and arrow indicating his readiness to destroy evils.His story forms the epic Ramayana. He is perfect in every aspect; the perfect man, the perfect husband, the perfect brother, the perfect king, etc. and the obedient son. Commonly he is pictured in a family style, with his wife Sita, and brother Lakshman.
In KRISHNA Avatar, Lord Vishnu incarnates himself as KRISHNA , the central character in the epic MAHABHARATA. In this biggest epic of Indian mythology a myriad of topics are covered, including war, love, brotherhood, politics etc. It is essentially the story of two warring groups of cousin brothers, the PANDAVAs and the KAURAVAs. As a part of the Mahabahrata, during the war KRISHNA, gives a long discourse to his disciple ARJUNA, collectively termed as Bhagvad-Gita. Krishna, during his child-hood was responsible for the killing of Kansa. Krishna is also considered to be an ultimate playboy who was resonsible for charming all gopikas (cowherdesses) around him. Unlike Ramayana, Mahabharata deals with more down to earth issues like politics, human nature, human weaknesses, and does not attempt to idealise the characters as in RAMAYANA. His death marks the beginning of Kali yuga.
With the departure of Lord Krishna (Krishna Avatar), the Kali yuga set in. In this age, the true devotion to Vedas was replaced by empty rituals. To enlighten the world, Lord Vishnu descended the earth as Buddha, the enlightened one.
He was born as the crown prince of the Kapilavastu to King Suddhodana and Maya. He was named Siddhartha, meaning "All thing fulfilled". But his mother died soon after his birth and was broughtup by Prajapati, the sister of Maya. Buddha was saddened by death of living creatures, and vices like poverty. He wasn't happy with any answers that were provided to him and he decided to find out the meaning and the absolute truth and he left his wife and child to a hermit's life in the forest and became the enlightened one.
His preachings spawned off the religion of Buddhism now popular across the whole world. Buddha advocated the Middle Path, in which he offered a balanced, harmonious way of life, steering between two extremes of self-indulgence and total abstinence. Buddhism rests upon four Noble Truths:
Suffering is universal,
It is caused by desire and yearning
Suffering can be prevented and overcome and
Eradication of desires can lead to removal of suffering.
To prevent suffering one has to conquer craving and desire and this conquest leads to the attainment of nirvana or complete enlightenment.
Kalki is believed as the next Avatar of Vishnu.
It is believed that He will appear, riding his white horse and drawing a flaming sword, at the end of the Kali Yuga, the dark age through which we are now passing. His task will be to exterminate the evil and restore the Dharma. Thus will begin a new cycle, starting with the new Satya Yuga.