The Epic of Gilgamesh is a highly refined nihilism, which describes the development of humankind, from animal to god. Gilgamesh is, as noted above, 2/3 part god and 1/3 human. The problem for him is not so much the composition of his being, but the failure to understand and take use of his possibilities as well as limitations. Gilgamesh wants to believe he is godlike, and thus do not have to face death, sadness or loneliness, as those are parts of the human fate. Therefore the gods decide to create Enkidu, as a mirror to reflect Gilgamesh and show him the true image of himself.
By closely following the development of Enkidu, we therefore also understand the development of Gilgamesh. Firstly Enkidu acts like an animal: he drinks from the river together with the herds and protects the animals from the hunters. When he has faced his true identity as a human being, he begins to understand the possibilities of being human; solving existential as well as practical problems, by finding an abstract idea and work to achieve it, by acting upon the ideal. Finally, after Enkidu dies, he realizes his actual limitation through mortality, and thus free his soul to live forever in the underworld, where he discovers the concept of eternity as a result of one's achievements during lifetime.
When examining these developments of Enkidu, we find that they correlate to the three stages of man: 1) hedonism, or the time when we're still so young that our focus and world view becomes centred around ourselves and our animalistic behaviour, 2) realism, or the time when we realize our small part as individuals in life as a whole, and that reality therefore isn't an equivalence to our ego, but that we must use our brain to create a change in the real world, 3) idealism, or the time when we accept our mortality as human beings and thus instead wish to live for the permanent things in life, which is the Ideal.
The life of Gilgamesh follows this pattern very closely: in the beginning of his time as a king, he believes he cannot die, and therefore have nothing to fear as an individual. As a result he becomes an immature and reckless leader, without being able to appreciate life for what it is, but life for what it could be. When Enkidu dies and Gilgamesh is forced to face his existential problems, he decides to travel with Urshanabi across the Ocean of Death, over to the Other Side where he will find the wisdom of life (Abzu, "The Depth"). His goal is to learn about himself and the world around him. This forms the connection between the material and ideal world, death and life.
One could see this as a process of nihilism, where all moral, ethical and utopian illusions are forced to pass through the filter of reality, until only ideas connected to truth are left. When Utnapishtim, lord of the Other Side, explains to Gilgamesh that he is not immortal - and all his attempts to take use of the secrets and possibilities open to immortality, fail - the once ruthless king now becomes a person in harmony with his inner soul. The mortal limitations, the 1/3 human part of his being, teaches Gilgamesh to not only live for the Ideal, but to accept and find meaning and beauty in reality, here and now, without sorting for the illusions that previously plagued his mind. He has become a nihilist and an idealist, loving and caring for his people and the village in which he lives.
By accepting his mortality, and thus his humanity, Gilgamesh paradoxically is able to live like a normal human being again - but at the same time fulfil his ideal as a god. For according to the ancient Sumerian texts, Gilgamesh actually becomes a god and continues to live for eternity. But an even more fascinating secret in this text is the fulfilment of the structural intent behind Gilgamesh's name. By splitting the name up into smaller words and translating them into separate concepts, then merging these together linguistically, 'Gilgamesh' translates into 'The Tree of Godlike Balance'. According to Sumerian mythology, the tree was seen as an organic connection between Earth and Sky, the life of the humans and life of the gods. The kings were often compared to a tree as in a spiritual hierarchy.
Understanding the three phases in the life of Gilgamesh, we also find a parallel to the linguistic meaning of his name: Gilgamesh is the king that rises from the earthly life and ends up becoming a god himself. He finds the connection between the material and the idealistic world; he achieves balance between ideal and reality, thus both becoming human but at the same time transcending all polarities and completing his 1/3 part to become 3/3 part god. Metaphorically we therefore see Gilgamesh as a tree, which forms a relationship between god and man, expressing idealism identical to the ancient Indo-European religion, where gods were a natural part of the reality of people.
This is a beautiful, transcendent work of prose, that much like the Edda or the Iliad, is an essential piece of read when one is up in the middle of life, looking for existential guidance, for truths and secrets, to open up a new gateway that will clear all illusions imposed on us by modern society, to free ourselves from the shackles of morality and guilt - and like Gilgamesh did - rediscover life to learn how to accept its limitations, possibilities, and inherent beauty; to learn how to live and love life as it really is.