A “Kafiristani” incantation recorded via Morgenstierne:
imro! delect machi mrhor o! o bagiShT o!
imro of the gods (delect ~ devaloka or godly realm) and of mortals the lord o! (c.f. devAnAm uta yo martyAnAM yajiShThaH); o the god baghiShT o!
The o in the incantation is likely a denasalized OM cognate.
The deity imro is the cognate of yamo rajan; The deity baghiShT seems to be a superlative formation from the same root as the I-Ir deity bhaga, who once enjoyed a popular Iranic cult. Comes in names like bhagadatta; baghdAd on both sides of the divide.
The position of the god yama is peculiar in early I-Ir tradition. The RV tradition is ambivalent towards him. He is presented as the might king and the son of the god vivasvat. While in some references, he is a god (e.g., ekaM sad viprA…). In others, he is contrasted with the god varuNa and it is hinted that he might be the first mortal. This is reiterated more explicitly in certain brAhmaNa texts.
This position is accentuated on the Zoroastrian Iranic side, where he becomes a mere mortal, albeit a primordial and important one.
However, there are clear hints that among the non-Zoroastrian Iranics, he had a more divine position (e.g., kuShANa seals). On the H side, in the AV tradition, his status as a god is clear (shared in part with KYV), and he comes along with rudra in some cases – this continues in the later epic and paurANika traditions.
His cognate in the Greek world is clearly divine.
However, based on the North Germanic tradition it is possible the two alternative traditions – the god of the dead/ghost world or the first mortal (probably cosmogonic) – existed in some form from the early IE tradition.
However, this surviving “Kafiristani” fragment, along with other ethnographic material, suggests that in their tradition, yama was a prominent deity as in the AV and, probably, branches of the non-Zoroastrian Iranic tradition. Interestingly, he is called the brother of the other prominent Kalasha-“Kafiri” deity Mone/made/mahandeu < mahAdeva.