According to the text, what was the reason for Sai Baba's incarnation in Shirdi and his subsequent departure?

According to Chapter 43, Sai Baba's manifestation had a clear and singular purpose: the welfare of his followers. The text states he "appeared in Shirdi for the sake of the devotees’ protection," drawn by their collective past merits and devotion. His work was entirely centered on them. Consequently, his departure is also framed in this context. The text explains that "now that the task for the devotees is over, they say he left the body." This was not a random event but the act of a Yogi who could die at will, choosing to burn his body in the fire of Yoga and merge back into his unmanifest form once his mission for the devotees was complete.