Vishnu is one of the most important deities in Vaishnavism, a major branch of Hinduism. He is considered to be the preserver and protector of the universe and is worshipped by millions of people around the world.

In Vaishnavism, Vishnu is believed to be the supreme being and the ultimate reality. He is often depicted as a blue-skinned, four-armed deity, adorned with jewels and holding a conch, discus, mace, and lotus flower. He is also known by many other names such as Narayana, Hari, and Govinda.

According to Vaishnavism, Vishnu has taken many avatars or incarnations in order to protect the world and restore balance and order. These avatars include popular figures such as Rama and Krishna, as well as lesser-known ones like Matsya (fish), Kurma (turtle), and Vamana (dwarf). Each avatar has a specific purpose and teaches important lessons to humanity.

Vishnu's role in Vaishnavism is multifaceted and encompasses various aspects. As the preserver, he maintains the balance of the universe and prevents it from falling into chaos. He is also known as the sustainer, as he provides nourishment and support to all beings. In this aspect, he is often depicted as reclining on the serpent deity, Shesha, in the cosmic ocean.

In addition to his role as the preserver, Vishnu is also believed to be the source of all existence and the ultimate goal of human life. Devotees of Vishnu seek his grace and blessings to attain moksha or liberation from the cycle of birth and death. This is often achieved through bhakti or devotion to Vishnu, as well as through performing good deeds and following moral and ethical principles.

In Vaishnavism, Vishnu is also seen as a compassionate and merciful deity who is always ready to help and protect his devotees. He is often depicted as responding to the prayers and pleas of his devotees, and is believed to intervene in the world to maintain dharma or righteousness.

Overall, Vishnu plays a central role in the belief system and practices of Vaishnavism. He is not only revered as a powerful deity but also as a loving and caring figure who guides and supports his devotees on their spiritual journey. His avatars and teachings continue to inspire and guide people towards leading a righteous and meaningful life.