Proto-Indo-Iranian religion stems from Indo-European with universal force *Hrta- and sacred drink *sawHma-. Indo-Iranian splits into Indo-Aryan, Iranian, Nuristani languages. Indic devas become Iranian daevas demons, Indra chief evil force after Angra Mainyu. Vedic Asuras turn malevolent while Zoroastrian Ahuras benevolent. Sarasvati battles serpent Vritra in Rigveda but peaceful river in Avesta. Shared sky god *Dyauš from PIE daylight-sky deity. Fire god *Hagníš identical in Sanskrit Agni and Avestan. *Mitras god of social order common to both branches. *YamHas mythical twin first Soma presser son of *Hwi(H)waswant. *Indras Vedic hero demon in Zoroastrian texts. Earth goddess *Pr̥tHwíH deified broad one. Dawn goddess *Hušā́s from PIE. Soma plant *sauma likely ephedra no IE cognate. Mythical weapon *uájra with Indra in India Mithra in Iran. Priest *j́hau-tar pours sacrifice. Truth order *Hrta upheld by Varuna and Ahura Mazda. Nuristani Kalash retain original Indo-Iranian influences. Reconstructed from Rigveda Avesta via comparative linguistics. Associated with Sintashta culture 2050–1900 BCE.