Sometime during the eighteenth century, Rammohun Roy, an educated revenue officer from West Bengal who was influenced by Christianity of the East India Company, founded the "anusthanic" Brahmo Samaj, a monotheist form of Hinduism that worships only one G-d.
In his book "Rabbi on the Ganges," Rabbi Alan Brill summed it up this way:
Brahmo Samaj and Ram Mohan Roy
The Brahmo Samaj was the first of the nineteenth century Hindu reform movements, founded in Kolkata in 1828 by Raja Ram Mohan Roy, thereafter resulting in the Brahmo religion in 1805 founded by Debendranath Tagore—better known as the father of Rabindranath Tagor. They strove toward a modernized, humanistic Hinduism with an eye open for societal problems. Ram Mohan Roy (1772-1833), born into a Brahmin family and the recipient of both Hindu and Muslim education eventually developed a strong symphony for the Unitarian Christians, even writing a work on the messages of Jesus. Roy eventually broke with Christianity and developed his Hindu reform movement. Roy’s most famous social reform is to campaign against window burning (sati). some of his other reforms included a rejection of Hindu pantheism, to be substituted with a more biblical notion of anthropomorphic monotheism; rejection of Hindu mythology, rejection of all iconic worship of “graven images,” rejection of sacrifices, and a repudiation of the doctrine of avataras. The Brahmo Samaj movement strove toward monotheism, rejected the worship of forms and idols, and no longer regarded the Vedas or the medieval Hindu classics as the sole religious authority. The Brahmo Samaj put forth principles that they widely circulated, of not adoring any created thing, no graven images and no animate or inanimate objects. One served God by performing good deeds, by promoting charity, morality, piety, benevolence and virtue, and through strengthening the bonds of union between men of all religions and creeds.
Is this faith considered Avodah Zarah? It seems as though Roy would hope not, for in his portrait he can be seen holding a Bible.