Who are the Olympians and what are they gods of?

The "Olympians" are the gods and goddesses of Mount Olympus, the pantheon of Greek gods.

They include:

Zeus: God of the sky and heavens

Poseidon: God of the sea

Hades: god of the underworld

Hermes: Messenger of the gods

Apollo: The god of music/the arts and medicine

Ares: the God of War

Dionysus: The god of wine

Hephaestus: God of fire

Athena: Goddess of wisdom and crafts/art

Aphrodite: Goddess of Love and Beauty

Artemis: The goddess of the hunt/nature

Demeter: goddess of earth and agriculture

Persephone: goddess of the underworld

Hestia: Goddess of the hearth and home

Hera: the goddess of Marriage and women (Zeus's wife)