According to the text, what is the true nature of a Sadguru and why does he take on a physical body?

Chapter 16 explains that the Sadguru, the King of Yogis, is truly the Stainless (Niranjana), the Imperishable (Avyaya), and One beyond attributes (Gunatita). He is an ocean of Truth, Consciousness, and Bliss. Despite this supreme, formless nature, the chapter clarifies that he has taken a physical body for a specific, compassionate purpose: to help others and to uplift the poor and the lowly. He dons a 'cloak of ignorance' only to be able to impart knowledge to the ignorant and provide sweet instruction to his devotees.