The Greek Gods and Goddesses

Greek gods and goddesses are given human form. but are first and foremost personifications of the forces of the universe. As such, they are more or less unchanging. While they sometimes seem to have a sense of justice, they are often petty or vengeful. The gods' favours are won by sacrifices and piety, but this does not guarantee them, for the gods are known to be prone to frequent changes of mind. Their anger is harsh and their love can be just as dangerous.
They only feared one thing, the blood of the Golden Hind which nullified their immortality from ichor.
The world of Greek mythology is quite complex. It is full of monsters, wars, intrigue, and meddling gods. In addition, there are heroes to help overcome these problems. To the Greeks, this was literally part of their history; no one (apart from a few skeptical philosophers) doubted the truth of the account of the Trojan War in The Iliad and The Odyssey. The Greeks used many of the myths to explain cultural variations, traditional enmities, and friendships, it was a source of pride to be able to trace one's descent from a mythological hero or a god.
In addition to the continuing use of mythology in literature, Grecian mythology today makes for some wonderful stories that remain enjoyable. Grecian mythology continues to be an important cultural reference long after the Grecian religion with which it was entwined ceased to be practiced. There was, to be sure, a Christian move to deface or destroy idols and other images that reflected the public cult of the gods when Christianity replaced paganism as the official faith of the Roman Empire. Literature posed a harder problem to the Christians; it would be impossible to erase the influence of Grecian mythology there without casting aside the Iliad and the other works of Homer, Theocritus, Vergil, Ovid, and hundreds of other authors that none but a few zealots were willing to cast aside. Grecian mythology thus has persisted for more than a millennium after the religion became extinct.

The Olympians

There are 12 Olympians (all in some way related to one another) who ruled the earth after overthrowing the Titans. They derived their group name from the place they lived Mount Olympus.
The Olympians are: Zeus, Poseidon, Hades, Hestia, Hera, Ares, Athena, Apollo, Aphrodite, Hermes, Artemis, Hephaestus.

The Titans

The earth was ruled before the Olympians by the The Titans. The ruler of the Titans was Cronus who was removed from power by his son Zeus.
Most of the Titans fought alongside Cronus against Zeus who after his victory punished them by being banishment to Tartarus. The Titans are associated with the various planets.

The Titans are: Gaea, Uranus, Cronus, Rhea, Oceanus, Tethys, Hyperion, Mnemosyne, Themis, Iapetus, Coeus, Crius, Phoebe, Thea, Prometheus, Epimetheus, Atlas, Metis, Dione.

Other nymphs spirits Iris, Moirae, Pan, Hebe, Hecate, Asclepius, Persephone, Aeolus, Eros, Eos, Muses, Echo, nymphs

Major heroes Heracles Bellerophon Pegasus; Theseus, Minos the Minotaur, Daedalus Icarus; Jason, Medea the Golden Fleece; Oedipus, Seven Against Thebes Antigone

The Olympians
Zeus	Poseidon	Hades	Hestia	Hera	Ares
Athena	Apollo	Aphrodite	Hermes	Artemis	Hephaestus
The Titans
Gaea	Uranus	Cronus	Rhea	Oceanus	Tethys
Hyperion	Mnemosyne	Themis	Iapetus	Coeus	Crius
Phoebe	Thea	Prometheus	Epimetheus	Atlas	Metis
Dione

Greek God and Goddess family tree see an easy to use graphical representation