A believer in Vishnu is a Hindu, which is a person who follows the religion of Hinduism. Hinduism is one of the oldest religions in the world and is based on the teachings of ancient scriptures known as the Vedas. It is a polytheistic religion that believes in multiple gods, with Vishnu being one of the most important deities. Believers in Vishnu worship him as the preserver of the universe and seek his protection and guidance.