{Greek mythology is the body of myths and teachings that belong to the ancient Greeks, concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices. It was a part of the religion in ancient Greece. Modern scholars refer to and study the myths in an attempt to throw light on the religious and political institutions of Ancient Greece and its civilization, and to gain understanding of the nature of myth-making itself }- obtained from Wikipedia .Greek mythology was one of the earliest mythologies.the story of the Greek gods said by the people was:-
"There were three children of the sky ; the sky was called Kornos the children were Zeus,Poseidon,Hades .Kornos was the titan of the universe .Kornos was the evilest thing ever expected in this whole universe.universe. Kornos tried to eat all three of his children but Zeus was very powerful and killed his father with the help of Poseidon and Hades..."
Now the real story starts:-
When they killed their father the most powerful son of Kornos : Zeus ; became the god of sky and Poseidon was made the god of oceans and Hades was made the god of underworld.From the second the made Hades the god of underworld Hades was not friendly with their brothers because he was to be in the underworld with the souls of the dead ....
These are the three main and powerful gods of Greek mythology................
{There are Twelve Olympians are the major deities of the Greek pantheon, commonly considered to be Zeus, Hera, Poseidon, Demeter, Athena, Apollo,Artemis, Ares, Aphrodite, Hephaestus, Hermes and either Hestia, or Dionysus.[1] Hades and Persephone were sometimes included as part of the twelve Olympians (primarily due to the influence of the Eleusinian Mysteries), although in general Hades was excluded, because he resided permanently in the underworld and never visited Mount Olympus.Heracles and Asclepius were sometimes included as well.}-obtained from Wikipedia..