What is the ultimate purpose of great souls like Sai Baba incarnating, and how does this relate to their relationship with mortality?

The primary purpose for the incarnation of great souls is the welfare and protection of people. As Chapter 43 elaborates, they are personifications of Brahman who appear on Earth to help others, often drawn by the merits of devotees. Their relationship with mortality is entirely different from that of ordinary beings; they are described as being beyond the womb and incarnating by their own will. The states of birth and death do not truly apply to these avatars. When their task is complete, they do not 'die' in the conventional sense but merge back into their true, unmanifest form. To suggest Baba was confined to his physical body is considered improper, as his true nature is one of unbroken prosperity.