Narada Muni

Sage Narada is a celestial musician and great devotee of Lord Vishnu. He was Manasaputra of Lord Brahma. He is best known as Kalaha-Priya (mischief monger) and  a wandering seer who always moves  with his Veena chanting “Narayana - Narayana”  

References :

Narada Muni’s reference is found in each and every Purana and all Yugas. Sage Valmiki also known as Adikavi, the first poet of the world, wrote “Ramayana” on the advice of the Narada Muni.  A robber by profession, he became a poet after he started chanting the name of RAMA.

Narada taught the Ashtakshari mantra OM NAMO NARAYANAYA to Bhakta Prahlada, son of demon king Hiranya Kasipa.