Within the Kularnava Tantra, the subtle body (sūkṣma-śarīra) is treated as the primary field of spiritual work, a sacred interior kṣetra in which the whole drama of realization unfolds. It is portrayed as a structured yet living framework of nāḍīs, prāṇas, and psychic centers that mediates between gross embodiment and pure consciousness. This subtle body functions as an inner altar, a mantric circuitry in which deities, śaktis, and mantras are installed and worshiped. Far from being a merely theoretical construct, it is regarded as the indispensable vehicle through which transformation occurs and through which the practitioner moves from ordinary awareness toward non-dual insight.

Within this subtle framework, the suṣumnā-nāḍī and the chakra system assume a central role. The chakras along the suṣumnā are described as lotus-like centers of concentrated spiritual energy, each associated with particular deities, mantras, and qualities. Kuṇḍalinī-śakti, residing at the base of the spine, is revered as the living presence of the Goddess, whose awakening and ascent through these centers is the inner counterpart of all external rites. The chakras thus become stations of worship and transformation, where gross energies are refined into subtler spiritual forces and where internal worship (antar-yāga) is patterned as a progressive movement through these loci.

Ritual and yogic practice in this text are consistently interiorized through reference to the subtle body and chakras. Mantra, mudrā, visualization, and related methods are prescribed to purify the nāḍīs, activate the chakras, and correctly “install” mantras in specific centers such as the heart, throat, and brow. Outer ritual (bahir-yāga) is treated as incomplete unless mirrored by this inner worship, so that the body itself becomes a temple and the subtle body its sanctum. Success in mantra and ritual is said to depend upon accurate engagement with this inner anatomy; ignorance or misplacement within it is portrayed as an obstacle to attainment.

All of this detailed subtle physiology is ultimately framed within a non-dual vision. The nāḍīs, chakras, and the rising kuṇḍalinī are understood as expressions of a single Śiva-Śakti reality, not as independent entities. As kuṇḍalinī ascends through the chakras and reaches the highest center, the apparent polarity of Śiva and Śakti is said to dissolve in unified awareness. In this way, the subtle body and its chakras are not only technical supports for practice but also a symbolic and experiential map, guiding the practitioner from stepwise, embodied worship to the recognition of indivisible consciousness.