(Source: https://threader.app/thread/1447434449222881285)
Who is the deity dhAtR? The later itihAsa-purANa place him in the Aditya class. In the RV it may be an epithet for multiple deities, but explicitly it mentioned as an epithet for visvakarman, who in turn is an epithet of the ancient tvaShTR. tvaShTR accompanies the the wives of the gods & other goddesses at the ritual. He appears in a similar role accompanying the sarasvatI and sinIvAlI in the sArasvata rite. There sarasvatI is also paired with the divine eagle deity (elsewhere tArkShyo ariShTanemiH or garutmant) manifesting in an androgynous aspect as sarasvant.
Thus dhAtR in the devikAyAga should be taken as an ectype of tvaShTR who retains his fertilizing aspect seen in sArasvata rite. In the somayAga the devikA-haviMShi are offered after the core agniShToma.
As standalone rituals with dhAtR in the beginning they are offered for offspring, after birth of offspring, cattle. The dhAtR oblations are placed in the middle of the goddesses for the gain of a village, for cure of prolonged illness & if the rituals are repeatedly ending in failure. For the illness an animal sacrifice is made to the goddesses. The dhAtR oblations are made after the goddesses if a yajamAna has completed key yAga-s or if a v2 has taken dIkSha for a rAjasUya. Other kAmya uses are to attempt to improve a dullwitted student and to acquire brilliance by placing the dhAtR oblations in the beginning and middle respectively.
(Elsewhere - )
(dhAtR) first appears as theonym of Tvaṣṭṛ in his aspect as Viśvakarman in RV 10.82.02. There Viśvakarman is explicitly described as Dhātṛ. The equivalence of Dhātṛ, Viśvakarman and Tvaṣṭṛ is established in the late Yajurvedic version of the Puruṣa-sūkta with the appendix termed the Uttaranārāyaṇa.