Lord Krsna is the Supreme Personality of Godhead and cause of ALL causes, and is the original Lord from whom all Vishnu/Narayana forms originate.

This beautiful boy Krsna is the Supreme Lord and cause of all living entities including all the Narayana and Vishnu Personalities of the Godhead who live on the permanent Vaikuntha Planets in the Spiritual realm.

Also there are three other Vishnus who manage and enter the temporary material creation -

1 - Maha Vishnu
2 - Garbhodakashayi Vishnu
3 - Paramatma

Paramatma accompanies the marginal living entities (jiva souls) when they choose to enter the material creation and take a material bodily vessel.