Why was Utnapishtim selected? Who selected him?

Utnapishtim is a major character in the final
section of the anonymous Babylonian epic of Gilgamesh. Gilgamesh, after the
death of his friend Enkidu, is seeking personal immortality and meets Utnapishtim on this
quest.

The story of Utnapishtim forms a backstory to the section of the epic
revolving around Gilgamesh's quest for immortality. As many critics have noted, the tale of
Utnapishtim is similar to the Biblical tale of Noah and the ark.

The god
Enlil was irritated by the incessant noise made by human beings and decided to annihilate all
human life by sending a giant flood. The god Ea disagreed with this choice and selected
Utnapishtim to build a giant boat and preserve his family, animals, and possessions through the
flood. The reason for this choice was because Utnapishtim was considered pious and virtuous, but
few other details are given. In Gilgamesh, Utnapishtim is portrayed as
wise, loyal, modest, and pious, and thus deserving of the immortality he was granted.