How was Hades important to the Greeks?

Answer 1

As well as being King of the Underworld (called Zeus Chthonius; Zeus of the Underworld) the Greek's regarded him as the god of all material wealth found within the earth, which was his realm.

Also, he was considered a god of earth's fertility, for each year he released Persephone in the spring.

Hades was regarded as the master of dreams, especially those believed to have been sent forth by the ghosts of the dead. The two-doored gate of the dreams (false and true) was said to lie in Hades' realm.

He was the god of potiant curse-oaths and master of the Furies, goddesses of vengeance against those who had committed a crime.

Hades was invoked and propitiated in the magic of Necromancia, the summoning forth of the ghosts of the dead. Hades and Persephone presided over the oracles of the dead (necromanteia) and the rites of necromancy (necromancia), the summoning of the ghosts of the dead.

Hades was god of funeral rites and mourning. Those who had not received proper burial rites were refused entry to the Underworld.

Most well remembered in the modern world is that Hades was the king of the underworld and ruler of the ghosts of the dead.