Based on Chapter 48 of Sai Satcharitra, what are the primary characteristics that define a true Sadguru?

Chapter 48 of the Shri Sai Satcharitra provides a detailed description of a true Sadguru. A Sadguru is defined not by mere scriptural knowledge, but by direct, full self-experience. He possesses the authority to enlighten disciples because he can give them this taste of experience. A Sadguru is also characterized by a complete lack of egoism, treating the disciple as Supreme Brahman with fatherly love. As described in this chapter, a true Sadguru never desires service from a disciple but is instead willing to sacrifice his own body for the disciple's sake, viewing all, small and great, as equals.