Ekapada represents the Axis Mundi (cosmic pillar of the universe) and portrays Shiva as the Supreme Lord, from whom Vishnu and Brahma originate.
In his back hands, the four-headed Brahma holds a sruk (a large wooden ladle used to offer ghee in fire-sacrifice) and a kamandalu (water-pot), while Vishnu—who is adorned with a kirita-mukuta (conical crown)—holds a shankha (conch) and chakra.
A third Agama text, the Uttara-Kanikagama, mentions that the figures of Brahma and Vishnu are proportionally smaller, similar to the size prescribed for female deities.
"[3] In South Indian temples, the icon may be accompanied by yogis or ascetics worshipping it and by the vahanas of the Trinity: Brahma's hamsa (swan/goose), Vishnu's garuda (eagle-man), and Shiva's Nandi bull.
Though he has his characteristic one leg, matted hair and crescent moon headgear, and ascetic attendants, here Ekapada is never depicted with the torsos of Vishnu and Brahma.
He sports a short beard and moustache, an open mouth with fangs, and bulging eyes with a wrathful expression.
[6] The Vishvakarma-shilpa mentions Ekapada as one of the Rudras and describes his iconography as having 16 arms and holding in his left arms a khatvanga, an arrow, a chakra, a damaru, a mudgara (a mallet-like weapon), an akshamala, and a trishula (trident), with one hand held in varada mudra, and with his right hands holding a bow, a ghanta (bell), a kapala, a kaumudi (crescent moon), a ghata (pot), a parashu (battle-axe), and shakti (power), with one hand in Tarjani mudra (with raised or threatening forefinger symbolizing wrath).
Aja Ekapada is closely associated with Ahi Budhnya ("serpent of the deep ocean"), appearing in juxtaposition with the latter in five Rigvedic hymns and once without him.
[9] According to another interpretation, Aja Ekapada appears to be an aerial deity since he is invoked as the supporter of the sky and the thundering flood.
Some scholars associate him with storms and interpret Aja Ekapada as a lightning strike coming down on earth in a single streak.
In the Hindu epics, Aja Ekapada, spelled Ajaikapada, is described as one of the 11 Rudras and an epithet of Shiva, an identification that still is in vogue and is reflected in most of his representations.
[9] Ekapada icons are found in most of the important Shiva temples in South India,[14] "in some place or the other", at least carved on a pillar.
The earliest Ekapada icons in Orissa date back to the 8th century CE and are also found at the entrance of a caitya or as a guardian-attendant of the Saptamatrika goddesses, as an aspect of Bhairava.
Tantric texts explicitly associate him with the Vedic Aja Ekapada, fire/Agni, sacrifice, the cosmic pillar of the universe, and the Yogini goddesses, who are also linked to the Saptamatrikas.
[8] As a guardian of the Saptamatrikas, Ekapada became more terrible in appearance, with motifs of blood-sacrifice and his depictions limited to Tantric goddess temples.
[16] According to one theory, Ekapada may have inspired the popular Vaishnava icon of Jagannath, a deity depicted without legs but a single stump below the waist.