Achilles and Gilgamesh are both demi-god who fought many battles. Being demi-gods made them far superior to ordinary men. Achilles was a hero of Trojan War who was consumed by fury which led to his short but glorious death. Gilgamesh was a brute King who later on became a hero who tried to find immortality but failed. The main similarity that I find between these two characters is that both lost a dear friend of each own. Achilles had a friend in the name of Patroclus who died on the battlefield. His death paved the way to his so called eternal fame. First, he killed the Trojan warrior prince Hector and then died later in the hands of Paris. Gilgamesh best friend was Enkidu, who was cursed by a Goddess to death. His death made him seek eternal
