Shivaji Sawant is the correct author of 'Mrityunjaya', though it's important to note this is a Marathi novel, not Hindi literature. The novel retells the Mahabharata from Karna's perspective. Munshi Prem Chand was a Hindi/Urdu writer, Bankim Chandra Chattopadhyay wrote in Bengali, so neither could have authored this Marathi work.