In Chaitanya-charitamrita (2.20.263-264) it is stated that the "avatar, or incarnation of Godhead, descends from the kingdom of God for creating and maintaining the material manifestation. And the particular form of the Personality of Godhead who so descends is called an incarnation, or avatar. Such incarnations are situated in the spiritual world, the kingdom of God. When They descend to the material creation, They assume the name avatar." The Srimad Bhagavatam states that there are countless incarnations just like the waves of the oceans. They fall in various categories like lila (pastime), yuga (period of yuga), manavantara (period of Manu), purusa (Vishnu expansions) and shaktivesa (empowered). These avatars perform various pastimes based on the time, place and circumstances, but their purpose is always the same - "to attract the conditioned souls back to their eternal spiritual abode". The incarnations emanate from Vishnu. Maha-Vishnu is the original cause of all material creation and from Him Garbhodakashai-Vishnu expands and then Ksirodakasayi-Vishnu. Generally all incarnations appearing within the material world are plenary portions of Ksirodakasayi-Vishnu (also known as Hari). However only once in a day of Lord Brahma (which lasts for 4.32 billion of our years), does Krishna descend in His original form, as the avataree, the cause of all avatars. When Krishna appears all the incarnations join with Him. The Supreme Personality of Godhead is the complete whole and all the plenary portions and incarnations always live with Him. So when Krishna appeared, Lord Vishnu was always with Him, and while Krishna enjoyed His pastimes in Vrindavan, the killing of the demons was actually carried out by the His Vishnu portion. Since Krishna eternally resides in Vrindavan, when He left Vrindavan at the age of ten, it was His Vasudeva expansion that actually left.
Supposed to be the most famous among the spiritual Hindu crowds, Krishna, is a well-known mythological hero in other countries as well due to the Hindu perception. Many pay tribute to him saying “Hare Krishna”. But, here the discussion would continue whether we revere him as the God or a common character?
According to the tales, associated with the Hindu religion, Krishna is an umbrella phrase of reference for a whole host of Gods who come under the same name. There are a number of Krishnas and when all of them put together, it creates a real baffling package certainly. Majority of people have an opinion that they think and talk about one Krishna, but in reality the subject matter is really diversified and it’s even tougher to come to a particular conclusion with proper and appropriate evidences.
The stories and mythological tales, linked with Krishna, however, are charming. And all these stories would have pleased him. Probably, he is the one deity who is praised and revered for his all naughty activities and speeches. Here the concept is bit different in case of Krishna. It also could be the reason why Krishna is very popular among all the Hindu spiritual people. The denunciation and adoration that Krishna has got are fabulous. If we are concerned about the mythological, social, cultural and psychological aspects of Indian lifestyle, then Krishna is not the God or Avatar. He is one of the common characters of Hindu mythology.