The character known for seeking immortality in Mesopotamian mythology is Gilgamesh, the hero of the Epic of Gilgamesh. His journey to find eternal life arises after the death of his friend Enkidu, leading him to embark on dangerous adventures. Despite his efforts, Gilgamesh ultimately learns that mortality is an inherent part of the human experience. His story emphasizes the significance of friendship, the inevitability of death, and the pursuit of life's meaning beyond just enduring forever, shaping the narrative of humanity's relationship with mortality.