Ea

Ea is the most powerful Noble Phantasm of Gilgamesh. It originally is a weapon with no name, and Gilgamesh is the one who calls it like that.

Enuma Elish, the Star of Creation that Splits Apart Heaven and Earth (天地乖離す開闢の星 Tenchi Kairisu Kaibyaku no Hoshi), is the space-ripping attack of Ea, the Sword of Rupture (乖離剣 kairiken).

By compressing and releasing wind pressure, it creates a space-time dislocation that pulverizes any enemy. With an output power surpassing Saber's Excalibur, it is the "sword that cut the world apart". Strictly speaking, the Noble Phantasm is Ea, and Enuma Elish is the name of the attack at its highest power.

Digressing a little, this drill shaped-sword was modeled after a bedrock drill made to dig undersea tunnels. As far as drills go, it somehow looks like it was crossed with a spear, with multiple gears piled up to dig a gigantic hole. The three parts of the blade spin separately, as if it was eating bedrock little by little.

Source: Fate/Side Material encyclopedia entry for Enuma Elish (p.66)