Hellenism

Hellenism, also called Hellenic Polytheism, is a religion that worships the Greek/Roman gods and generally attempts to continue the religious traditions of ancient Greece.

Hellenism is basically the religion practiced by Greek demigods when they bother to be open about their belief in/worship of the Olympians. It is used as an explanation for why they swear to Zeus or on the River Styx instead of to Jesus, why they sacrifice portions of their meals, and so on. The religion however is practiced by humans as well.

After the mist begins to decay in The Sundered Veil, Hellenism increases in popularity as more people learn that Greek Mythology is true and the Greek gods are real. Most Hellenic pagans have one god they worship above others. As was the case in ancient Greece, not every deity or even ever major deity, is worshiped by everyone. The two major exceptions to this are Zeus, because he is the king of the gods, and Aphrodite, because pretty much everyone can relate to being in love or lust.

Hellenic Temples across America are autonomous entities.

Hellenism vs Church of the Blind God
The Church of the Blind God acts as a foil to Hellenism. The Blind Church acknowledges that the Olympians (and other pagan deities) exist but refers to them as "false gods" and views them as demons to the opposed and demigods as abominations.

Hellenism and the Church of the Blind God have opposing views on sexuality as well. The Blind Church emphasizes sexual purity and monogamy and are generally opposed to LGBT rights.