GILGAMESH IN THE SERIES
Gilgamesh in The Secrets of the Immortal Nicholas Flamel is described as the oldest Immortal in history. He now currently lives in London as a homeless man, and is described as being quite crazy. He posseses a large amount of knowledge regarding the magics of Earth, Air, Water, and Fire. Flamel brings the twins to him with the intention of having them learn Water Magic, but Gilgamesh initially refuses due to a time when Flamel tried to kill him. He also reveals to Sophie and Josh that they are not the first twins that Flamel and Perenelle have sought out, leading them to distrust Flamel a lot more. Gilgamesh is described as an old man in the series.
In The Sorceress, Gilgamesh is picked up by Flamel, the twins, and Palamedes as they speed away from the attack by Cerunnos. They eventually pull over at an old barn in the middle of nowhere. Gilgamesh makes notes to remember important events, including when Sophie cries for him. Before he teaches them Water Magic, he makes Josh and Sophie promise that when all this is over, they will bring him the Book of Abraham, to which they agree. Gilgamesh is barely able to teach Josh and Sophie Water Magic when Cerunnos attacks, shooting an arrow into Gilgamesh's chest and wounding him. He makes Sophie and Josh use water to stop Cerunnos, and then advises them that he will live. It is assumed that he is now living again, but it remains to be seen in the series.
GILGAMESH IN LEGEND / MYTHOLOGY
Gilgamesh today is remembered in the Bablyonian saga, The Epic of Gilgamesh. This story and saga is said to be older then the Bible. It has recently with certain archeological discoveries been thought that the character of Gilgamesh in the Epic is based on a real life king, who ruled the city of Uruk in ancient Mesopotamia circa 2700 BC. In the list of Babylonian kings, he is known as Bilgames. Despite the theories, there has yet to be hard proof given of the existence of Gilgamesh as a real person.