Gilgamesh was the fifth king of Uruk, a Sumerian city-state in ancient Mesopotamia (present-day Iraq, in the Middle East), around 2500 BC. Several centuries after his reign, he was immortalized as the central character in the Epic of Gilgamesh, which is the most complete piece of Babylonian literature and mankind's oldest epic.
The Epic of Gilgamesh was the basic archetype for nearly all epic stories that came after, including literature, movies, and video games, especially role-playing games.
As the first mythological superhero in history, Gilgamesh has superhuman powers, and is the basic archetype for most heroes and superheroes in history. He may also be considered the first anti-hero in history; due to the differing morals of his day, many of his traits can be deemed both heroic and anti-heroic at the same time.
Epic of Gilgamesh
Gilgamesh is a 2/3 god and 1/3 human king who ruled the Sumerian city of Uruk (in Mesopotamia, present-day Iraq) in 2600 BC. He was the king of heroes whose tale is recorded in mankind's oldest surviving recorded epic poem, "Epic of Gilgamesh".
Gilgamesh was originally a tyrant who did not care for his people. The Goddess Aruru created Enkidu in response to the prayers of the people to befriend Gilgamesh. Gilgamesh recognized Enkidu as an equal they ruled the city fairly.
Gilgamesh and Enkidu defeated Humbaba, guardian of the forest and beast of the gods, and became the greatest and richest king on Earth. Ishtar, the goddess of fertility, fell in love with Gilgamesh. He rejected her because he knew her as unfaithful, cruel, and a corrupter of men.
Ishtar was infuriated and wanted revenge. She requested her father Anu to unleash the Bull of Heaven. It caused 7 years of starvation and destruction on earth. Gilgamesh and Enkidu managed to defeat it, further propelling his reputation and crushing Ishtar's reputation.
Ishtar then requested that Enkidu be struck down for killing a beast of the gods. Gilgamesh was shocked that Enkidu, whom he sees as an equal, could die. He was tormented by the fear of death and he traveled to the Netherworld to find a way to defy death.
After the long and arduous journey, Gilgamesh managed to obtain the elixir of immortality. On the way back, the elixir was stolen by a snake and Gilgamesh died of grief. It is said that the snake drank the elixir, shed its skin, and began a new life.
His first appearance in video games was as Gil in the 1984 arcade proto-action-RPG, The Tower of Druaga, where he was interpreted as a heroic young man on a quest to rescue his lover Ki. The game's success led to the Babylonian Castle Saga franchise, revolving around the adventures of Gil and Ki. Unlike the real Gilgamesh, however, Gil lacked anti-hero qualities, up until the 2009 anime sequel, The Tower of Druaga: The Sword of Uruk, where he plays the role of the antagonist, or anti-villain (i.e. hero turned evil).
A more accurate depiction of Gilgamesh came in the 1985 adventure game Rivers of Light, based on the actual Epic of Gilgamesh, packaged with the computer game Adventure Construction Set.
The most well known video game interpretations, however, are the antagonists, Gilgamesh in Final Fantasy V (also appearing in subsequent Final Fantasy games) and Gilgamesh in Fate/Stay Night (the most powerful villain in the Fate franchise). While Final Fantasy V only uses his name, Fate/Stay Night is based on the historical figure, with his backstory based on the Epic of Gilgamesh.
Gilgamesh also makes an appearance in the Marvel franchise as the Forgotten One (also known simply as Hero), one of the most powerful superheroes in the Marvel universe.