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.