From Buddhism there will be a linkage as both stem from Aryanic religions -- the Zoroastrians from Iranic and the buddhists from Indic
I think if you look at Aryanic/Indo-European religion, the basic idea is of two families of god -- Devas/Daevas and Asuras/Ahuras
In the lowest form, the Nordics these are two nearly equal "families" of the Aesir and Vanir. In the Celtic this may be the basis for fairies.
In Greek (highly developed) and Latin (not developed but borrowed heavily from the Greeks, Etruscans, Phoenicians etc.) there is one family (Olympians) overthrowing an early, related family (Titans) -- names of the gods also tie across the three (Deus in Latin, Zeus in greek, Dyaus Pitr in Sanskrit -- meaning sky father)
In the advanced religions of Indo-Irani Aryanic cultures you see the highest development of these. among Indics you see the initial thrust of equal levels of gods, with in fact the higher Devas like Varuna or Agni called Asura almost like "Sir God!", but later Vedic Hinduism sees the Asuras reduced to lesser supernatural beings (not quite demons), then post Jainism (700 BC) and Buddhism (400 BC) the Asuras become evil supernatural beings and post the influence of Christianity (Christianity reached India in Apostolic times thanks to St. Thomas), the Asuras became demons
in Iran the opposite happened with the Ahuras ("s" in Indic becomes "h" in Irani languages hence Sindhus became Hindus) gaining prominence and the Daevas becoming purely gods of the hearth (akin to the Roman "genius" of the house), until Zoroaster came along and said all of these are just symbols/not gods - the real God is Ahura Mazda the God of Light and his counter-force Aingra Mainyu
Buddhism arose out of Vedic hinduism, but more clearly out of Jainism (founded by Mahavira Jaina in 700 BC but claiming eternal existence)
Jainism arose from a time when Vedic Hinduism was decaying. Vedic Hinduism which predates 1700 BC (supposed to be the time when the Rig Veda was composed) details a religion that has a strong emphasis on yagnas i.e. fire sacrifices including horse sacrifices (the highest sacrifice indicating the horseback origins of the Indo-Europeans like the Hittites in Anatolia) and then the Rishis (holy men who meditated a lot and had powers) dominating Hinduism.
Hinduism also began to stagnate as monasticism reached its peak and then Jainism came with the radical strong ahimsa, utter veganism, etc. ideas. along with the rejection of a creator deity and indeed of creation or destruction.
Buddhism took this and made it "lighter"
Very interesting. Thanks C.