What is the lineage of Shri Saraswati Gangadhar and what is its significance to the 'Guru Charitra'?

Chapter 0 explains the ancestral connection of Shri Saraswati Gangadhar to the 'Guru Charitra'. His family, with the surname Sakhare, had an ancestor named Shri Sayandev who received the direct grace of Shri Narsimha Saraswati Maharaj, the protagonist of the 'Guru Charitra'. According to the text, Shri Sayandev received a divine boon that his descendants would be in constant service to the Guru. Fulfilling this familial and spiritual destiny, Shri Saraswati Gangadhar, who is identified in Chapter 0 as the fifth descendant from Shri Sayandev, authored his renowned Guru biography.