My essay investigates a short passage of the Guhyasūtra-the longest, most detailed, and arguably youngest of the 'Sūtras' constituting the Niśvāsatattvasaṃhitā, being the earliest Śaiva Tantra known to us. This is formed by verses 1-22ab of Paṭala 12, which single out the soteriological means and goals specific to such scantily documented Śaiva groups as the Pāñcārthika Pāśupatas, the followers of the Pramāṇaśāstras, the Kārukas, and the Vaimalas. By categorizing such groups according to their emphasis on conduct, initiation, or gnosis, the text presents a taxonomy of the Atimārga as seen from the perspective of Mantramārga Śaivism. Having compared, and contrasted, this model to analogous ones found scattered over the extant literature of the Śaiva Mantramārga, I tackle the issue as to whether those taxonomies reflect actual social realities or are the result of post hoc systematising attempts by medieval authors.