Gaghiel has a very large body, matching in size to Iowa-class battleships (which are about 270 meters long), and easily overshadowing an Eva. It has very large jaws, filled with sharp serrated teeth. Its core is also located in its mouth. Its skin is tannish in color, with a black outline. It is a strong and durable angel, destroying many of the UN Pacific fleets ships with its body. It also has a face-plate yet again resembling the one Sachiel grows after being attacked by an N2 mine. However, it does not generate a visible A.T. Field, though it uses it to some degree, as it is not damaged by the firepower of the fleet.

Gaghiel literally means Roaring Beast of God. It is named after the Angel of the Fish. His appearance resembles the Leviathan, a gigantic mythological sea monster, that appears in the book of Job and is usually compared with the crocodile or the whale. It´s sometimes associated with Lucifer, the fallen angel.