Gilgamesh
A Sumerian king and ruthless ruler who abused his power and subjected his people to oppression.

Enkidu
A man/beast created by Aruru - the Sumerian creator goddess (at the request of the populace of Uruk) to defeat Gilgamesh.

An/Anu
The "creator" god of the Sumerian pantheon, and father of the gods.

Enlil
The leader of the Sumerian pantheon (Anu relinquished his power to Enlil at some point), who was the instigator of the great flood.

Ea/Enki
The god of the waterery depths of the Abzu who betrayed the pantheon by revealing to Utnapishtim that Enlil was to destroy humanity by a great flood.

Inanna/Ishtar
The Sumerian goddess of love and sexuality who attempts to seduce Gigamesh. Knowing her history of sordid and failed love affairs, Gilgamesh refuses her advances causing much strife for himself and the people of Uruk.

Ninsun
The mother of Gilgamesh and priestess of the temple of Uruk. She helps Gilgamesh interpret his dream about a falling star, and makes Utu/Shamash protect Gilgamesh on his journey to the Cedar Mountains.

The Bull of Heaven
The god of the stars, affiliated with the constellation of Taurus. Inanna sends the Bull to destroy Gigamesh, Enkidu and Uruk.

Huwawa/Humbaba
Enlil's guardian of the great forest in the Cedar Mountains. He has seven layers of "terrifying radiance" which blinds his enemies. He is a very powerful god.

Utu/Shamash
The Sumerian sun god, who assists Gilgamesh and Enkidu in their battle with Huwawa/Humbaba because of a promise to Ninsun to protect Gilgamesh.

Siduri
An Innkeeper who gives Gilgamesh some solid advice in the "Far Away".

Ziasudra/Utnapishtim
The survivor of the great flood, who was once mortal. The god Ea/Enki (god of the waters) tells Ziasudra/Utnapishtim to build an ark to survive the great flood. As the only human left to survive the flood the gods feel remorse and make him immortal. Gilgamesh seeks him in his search for immortality.