Gon Nu earned the nickname "Supreme General" of Kummen's foreign legion, and he leads the largest mercenary force in the kingdom. His force was the first to deploy the ATH-06-WP "Diving Beetle", using it to drive Veela Guerrillas out of the capital city Zaiden, and keep them on the defensive throughout the nation. With this AT at their disposal, Gon Nu's forces become known as the "Vella Killers."

Residing at Assemble EX-10, Gon Nu is a manipulative but fair-minded officer who is not above shady means to pursue his interests, which are usually financial in nature. This even includes a pact with the Melkian army in its continuing pursuit of the Perfect Soldier Prototype.