आगमे विश्वासटिप्पन्यः

A sibling of the Arya deva-dharma, a child of the ancestral Indo-Iranian branch of Indo-Aryan. They shared several deva-s with the Arya-s.

Rituals

“Iranians, like their Indic counterparts, were largely un-iconic in public ritual to start with, probably using icons only in small private shrines.”
“On the eastern front things were dramatically different, with Iranians receiving iconographic inputs not just from the Greeks but also Indians. For example vAyu of the Kushanas inherits his iconography from rudra in India. … The goddess aredvI sUrA anAhitA, the sarasvatI ortholog, was one of the Iranian deities to receive an iconic representation from very early on. It appears that even Artaxerxes-II, who had a special devotion to this goddess, might have founded iconic temples of hers at Hamadan, Babylon and Damascus. In the early period her iconography was influenced by Semitic goddesses such as Ishtar. But in the eastern zone of the Iranian territory her iconography was clearly influenced by chaNdikA or durgA.”

Via MT .

The dastavara expounded the that the power of ahura mazdA and the amesha spenta-s is constantly opposed by the power of druj. As a result both the mere Iranian mortal and the learned ritualist are ever prone to being deluded.
Due to the delusion of the druj, his apprehension of haithya (=satya in devabhAShA), which is derived from his study of the avestan recitations and rituals and observation of the universe, can be false. Thus, even though he might think that he grasps the haithya, what he performs and declares as the haithya might not be the real thing. So he must always have safeguards against the danger of falsehood being presented as haithya.
First he must seek to understand the ratu-s, with which ahura mazdA and the yazata-s generated the universe, the ratu-s of the yasna, and those used by thworashtar, the divine fashioner. Thus, he must have a firm understanding of the 33 great ratu-s, which are embedded in the structure of the of haoma yasna (yasna 1 and 6 of the avesta).
He must utter at the right points in the ritual the incantations that serve as patches to the ritual to contain and counter the effects of his misapprehension.
In course of the yasna session he should engage in questioning sessions that help in arriving at the haithya.

From MT: “On 3rd day after an Iranian dies he is said to arrive at the bride of the dead known as the cinvato peretu. There if has performed puNya-s he is met by the goddess daena with her dogs in the form of a beautiful woman who gives him a divine drink. If he has performed pApa-s instead she arrives as a dreadful harridan and he is borne away by the dogs to be judged by raShNu and sraosha. The dogs may be identified with constellations of Canis Major and Minor and the Chinvata bridge with the Milky Way.”