The supremely beautiful and distinctive image of Lord Paśupatinātha Mahādēva at Kathmandu, Nepal, is adorned with four visible faces:
1. Sadyōjāta
2. Vāmadēva
3. Aghora
4. Tatpuruṣa
The fifth and invisible face of īśāna together with the other four faces forms a Pañcamukha Mahāliṅga. Our śrīkula Krama Tantra of Bimbāmbikā Sampradāya which flourished prosperously in Nepal during certain periods describes the following names for the five faces:
1. Mahādēva (pūrvamukha, Pūrvāmnāya)
2. Bhairava (Dakṣiṇamukha, Dakṣiṇāmnāya)
3. Nandivaktra (paścimamukha, Paścimāmnāya)
4. Umāvaktra (uttaramukha, śāktāmnāya)
5. Sadāśiva (ūrdhvamukha, ūrdhvāmnāya)
The base of the liṅga represents the Adharāmnāya. The above epithets with respective mantras (Kramakalpalatā, Pāśupata krama, verses 18-39) are used today in the temple during ritualistic worship thrice every day. (The ritualistic manual used in the temple was given to me graciously by Sri Girish Bhatta of Dakshina Kannada, who is now one of the chief priests at the shrine).
It is commonplace in history and hagiography that Shankara Bhagavatpādācārya was responsible at a crucial period in time for the regeneration of the Dharmic way of life and religious practice and for extended devotional support to śāktamata in its twin forms dealing with Prakr̥ti and Puruṣa. In keeping with the general practice set in vogue by the ācārya said to be associated with this shrine, śivābhinnā Parāśakti is worshiped in the shrine of Paśupatinātha in the form of śrīyantra placed above the liṅga, representing Mahāripurasundarī as Pañcabrahmāsanasthitā. She is worshipped with various offerings and tarpaṇa using the Parāṣōḍaśī mahāmantra and the ṣōḍaśāvaraṇa krama. After all, the most distinctive aspect of even the ūrdvarētaska form of Yōgīśvara Mahādēva, along with his supreme control over the senses, is his intimate and uninterrupted contact with śakti. This gets stated beautifully in Mālavikāgnimitra:
kāntāsammiśradēhō’pyaviṣayamanasāṁ yaḥ parastādyatīnām ||
The statement in the Māhatmya khaṇḍa of Tripurārahasya describing the śrīcakra present on a pañcamukha liṅga as the most auspicious among daśa kōṭi śrīyantras seems to be an explicit indication of Paśupatinātha. The worship manual used by the priests in the shrine describes Mahātripurasundarī as the central deity commanding a greater priority than even our dear poor Mahādēva (śarīrārdham śambhōraparamapi śaṅkē hr̥tamabhūt, prōktā śivavyāpinī, etc.) and her worship above the Pañcabrahma liṅga is described as granting Yoga-siddhi. This also points to the popularity of śrīvidyā school in Nepal especially among the priests of the temple as also several generations of rulers of Nepal as well as the popularity of śakti upāsanā in general across the length and breadth of this small country, including overlapping spheres of Tantric Buddhism.
The six yogas associated with the six aspects of the liṅga and āmnāyas that are attained by the worship of Mahātripurasundarī (Kāmakalā Kālikā) and Paśupatinātha (Kāmēśvara Bhaṭṭāraka or Mahākāla Kāmēśvara) are:
1. Adharāmnāya: śabda yōga
2. Pūrvāmnāya: Mantra yoga
3. Dakśiṇāmnāya: Bhakti yoga
4. Paścimāmnāya: Karma yoga
5. Uttarāmnāya: Jñāna yoga
6. ūrdhvāmnāya: śakti yōga or mōkṣa yoga
These seem to be based on the model of six yogas described in Rudrayāmaḷa with Laya yoga replaced by śabda yoga.