The correct answer to this open question is the following.
The Epic of Gilgamesh is one of the ancients books or documents known to historians. It is probably the first one in the history of humanity. It relates to the life and adventures of Gilgamesh, in ancient Mesopotamia.
Yes, in the story, Gilgamesh's relationship with Enkidu teaches him many life lessons.
One of the lessons that he learned on his journey is the persistence to accomplish what you want, despite the toughest circumstances. The other lesson is that death is inevitable. It is part of the life of humans, It is the end of the trip.
Gilgamesh is presented as 1/3 human and 2/3 god while Enkidu is presented as half human and half animal before he is "tamed" because according to the story and the narrative of the Sumerians, it was the gods who came to earth from the sky. They were known to be giants and had special "knacks" or characteristics. When these gods married human women, then, they breed a rare mixture of humans with other species.
Those texts can be found in the famous clay tablets of the Sumerians.
