Amongst the Zoroastrians, the dragon-slayer is known as Fereydun, or more archaically as Thraetaona. Who is, curiously, the son of the Zoroastrian figure of Tritas / Thrita. Now, for the Zoroastrians, there is no Indra – except in their lists of demons. As is well known, when they began their heresy against the previously prevalent Indo-Iranian religious orthodoxy, they sought to cast down The Gods and declare the Devas to be malefic demons, so as to exalt their own belief in Their righteous place. So, it should come as no surprise that the act of dragon-slaying is more cleanly ascribed to this Fereydun. Although it is interesting indeed that the Zoroastrian ‘sanitized version’ of Indra – Verethragna – despite having a name that is a direct derivative of the Vritrahan epithet we encounter in relation to Indra in the Vedic religion … does not carry out an act of dragon-slaying. Evidently, Verethragna was ‘(re-)introduced’ to the officially sanctioned Zoroastrian mythology after Thraetona (himself ‘safely’ distanced from the old mythology by being the son of Third, rather than Third Himself) had already taken over the combined ‘Dragon-Slaying’ we would perhaps separately think of viz. Vritra and Trisiras; yet which, as we have already seen, appears to have been combined by the Greeks when dealing with the Hydra. [technically, there are at least a few other ‘resonant’ occurrences within the Greek mythology which seem to match the Trisiras conceptry rather well – the slaying of Geryon, and the later slaying of Cacus; but more upon those, perhaps, some other time).
The reason why I bring up the Zoroastrian account, is because it is occasionally argued by various academics that as there is such a concordance between the two major Indo-Iranian religions about this figure of ‘Third’ (or, at least, Third’s son) carrying out the dragon-slaying … that this means that Indra is a later interpolation into the tale – and therefore, in the more extreme versions of this theory, is a non-Indo-European deity all up, perhaps from the BMAC (Bactria-Margiana Archaeological Complex).
And I suppose that if one were to consider only the Vedic and Zoroastrian mythologies, and see that the only constant as applies the dragon-slaying is that it features the ‘Third’ figure and the Dragon, that it might perhaps make some sense to suggest that the original myth must only have had these two – with the direct involvement of the Striker/Thunderer being the later innovation, which eclipsed the more archaic ‘Third’.
Except evidently, that is not the case – and can only be arrived at via a misunderstanding, a misinterpretation of the Indo-Iranian evidence … and is rendered further implausible via the Greek expressions of the same mytheme that we have just countenanced. The original Indo-Iranian form of the myth must have had the Striker/Thunderer involved – for that is the broad, pan-Indo-European typology. The Zoroastrian version must have removed said Striker/Thunderer – for this is Who we find reduced to the status of a demon (alongside Rudra, and the Nasatya Horse-Twins, etc.) in their twisted reflection of our mythology. The presence of both the Striker/Thunderer and the ‘Third’ man is confirmed via the integral role played by Iolaus in the Hydra-Slaying of Herakles – which directly matches the features we find in the Vedic rendition of the tale.
Once again, a comparative approach establishes that the Vedic canon is the most comprehensive and accurate account – and that the attempts to ‘de-Indo-European-ize’ elements of its contents, its Pantheon, are ‘bright ideas’ looking for some spine to shiver up. And not Dadhichi’s.
However, there is one further element that must be noted here – and it is really quite fascinating.