Hellenic polytheists worship the ancient Greek Gods, including the Olympians, nature divinities, underworld deities (chthonic gods) and heroes. Both physical and spiritual ancestors are honoured. It is primarily a devotional or votive religion, based on the exchange of gifts (offerings) for the gods' blessings. The ethical convictions of modern Hellenic polytheists are often inspired by ancient Greek virtues such as reciprocity, hospitality, self-control and moderation. The Delphic maxims, Tenets of Solon, the Golden Verses of Pythagoras, or even Aristotle's Ethics each function as complete moral codes that a Hellenic Polytheist may observe. Key to most ethical systems is the idea of kharis (or "charis", grace), to establish reciprocity between humanity and the gods, between individuals, and among community members. Another key value in Hellenic Polytheism is eusebeia, often translated as piety. This implies a commitment to the worship of the Hellenic gods and action to back this up.
In Modern Hellenism there is a hierarchy of deities, with Zeus, the king of the gods, having a level of control over all the others, although he is not almighty. Some deities have dominion over certain aspects of nature. For instance, Zeus was the sky-god, sending thunder and lightning, Poseidon rules over the sea and earthquakes, Hades projects his remarkable power throughout the realms of death and the Underworld. Other deities ruled over abstract concepts; for instance Aphrodite controls love.
While being immortal, the gods are certainly not all-good or even all-powerful. The gods act like humans and have human vices. They interact with humans, sometimes even spawning children with them. At times certain gods would be opposed to others, and they would try to outdo each other.
There is no central "ecclesia" (church/assembly) or hierarchical clergy, though some groups (i.e., Hellenion) do offer training in that capacity. Individual worshipers are generally expected to perform their own rituals and learn about the religion and the gods by reference to primary and secondary sources on ancient Greek religion and through personal experience of the gods. Information gained from such personal experiences is often referred to in Hellenic groups as "UPG" (Unverified Personal Gnosis), a term borrowed from Ásatrú, though now commonly used among many pagan religions
The Olympians were the principal deities of the Greek pantheon, so named because of their residency atop Mount Olympus. They gained their supremacy in a ten-year-long war of gods, in which Zeus led his siblings to victory over the previous generation of ruling gods, the Titans. With the rise of Modern Hellenism, the gods have now been reborn on Mount Olympus and have turned their eyes to the mortal world.
APHRODITE
The Olympian goddess of love, beauty, pleasure and procreation. She is depicted as a beautiful woman often accompanied by the winged godling Eros (Love). Her attributes include a dove, apple, scallop shell and mirror. In classical sculpture and fresco she is usually depicted nude.
APOLLON (Apollo)
The Olympian god of prophecy and oracles, music, song and poetry, archery, healing, plague and disease, and the protection of the young. He is depicted as a handsome, beardless youth with long hair and attributes such as a wreath and branch of laurel, bow and quiver of arrows, raven, and lyre.
ARES
The Olympian god of war, battlelust, courage and civil order. In ancient Greek art he is depicted as either a mature, bearded warrior armed for battle, or a nude, beardless youth with a helm and spear.
ARTEMIS
The Olympian goddess of hunting, the wilderness and wild animals. She is also a goddess of childbirth, and the protectress of the girl child up to the age of marriage--her twin brother Apollon is similarly the protector of the boy child. Together the two gods are also bringers of sudden death and disease--Artemis targetted women and girls, Apollon men and boys.
ATHENE (Athena)
The Olympian goddess of wisdom and good counsel, war, the defence of towns, heroic endeavour, weaving, pottery and various other crafts. She is depicted as a stately woman armed with a shield and spear, and wearing a long robe, crested helm, and the famed aigis--a snake-trimmed cape adorned with the monstrous visage of the Gorgon Medousa (Medusa).
DEMETER
The Olympian goddess of agriculture, grain and bread who sustained mankind with the earth's rich bounty. She presides over the foremost of the Mystery Cults which promised its initiates the path to a blessed afterlife in the realm of Elysium. Demeter is depicted as a mature woman, often wearing a crown and bearing sheafs of wheat or a cornucopia (horn of plenty), and a torch.
DIONYSOS (Dionysus)
The Olympian god of wine, vegetation, pleasure, festivity, madness and wild frenzy. He is depicted as either an older, bearded god or an effeminate, long-haired youth. His attributes include the thyrsos (a pine-cone tipped staff), a drinking cup and a crown of ivy. He is usually accompanied by a troop of Satyrs and Mainades (wild female devotees).
HEPHAISTOS (Hephaestus)
The Olympian god of fire, smiths, craftsmen, metalworking, stonemasonry and sculpture. He is depicted as a bearded man holding a hammer and tongs--the tools of a smith--and sometimes riding a donkey.
HERA
The Olympian queen of the gods, and the goddess of marriage, women, the sky and the stars of heaven. She is usually depicted as a beautiful woman wearing a crown and holding a royal, lotus-tipped sceptre, and sometimes accompanied by a lion, cuckoo or hawk.
HERMES
The Olympian god of herds and flocks, travellers and hospitality, roads and trade, thievery and cunning, heralds and diplomacy, language and writing, athletic contests and gymnasiums, astronomy and astrology. He is the herald and personal messenger of Zeus, King of the Gods, and also the guide of the dead who led souls down into the underworld.
Hermes is depicted as either a handsome and athletic, beardless youth or as an older, bearded man, with winged boots and a herald's wand.
POSEIDON
The Olympian god of the sea, earthquakes, floods, drought and horses.
He is depicted as a mature man with a sturdy build and dark beard holding a trident (a three-pronged fisherman's spear).