I think the major theme of this epic is Man vs. the Natural World. In the epic Gilgamesh is represented as civilization (man) and Enkidu is represented by Nature (natural world). In the beginning of the story Gilgamesh is a mean young man that is just running around doing whatever he wants to do. No rules, no empathy on people, just him doing whatever pleases him. One day before he is about to go in and have his way with a bride an animal like man stops him, his name was Enkidu. Now Enkidu was dirty and not clothed because he lived like an animal, he didn’t even know how to really talk. They wrestling and fight it out and with Gilgamesh never having a single person beat him get beaten. After that afternoon Enkidu and Gilgamesh were best friends.
