How does Chapter 18 describe the fundamental nature of the Sadguru and the effect of approaching him?

Chapter 18 opens with powerful praises, describing the Sadguru as the supreme Eternal one and the ultimate Truth of Brahman. It states that the Sadguru is the ruler over Maya (illusion) and the teacher of self-knowledge. A powerful analogy is used to illustrate the effect of approaching him: just as a salt doll entering the ocean dissolves and cannot return, one who approaches the Sadguru merges with him, losing their individual identity. This chapter emphasizes that through his grace, the false logic of 'mine' and 'thine' disappears, showing his transformative power over devotees.