Gaia is a Japanese Wolf, leader of the soldiers of the Empire and the ruler of the Underworld. Mortal enemies with Reima's clan.

In the Wolf Arc in GNG, Gaia heard that there is a Battouga warrior that is not a wolf and orders to his minions to find him, they do find Gin but get defeated. Gaia had trained 8 wolves to become the eight canine warriors of Sirius and he doesn't give up even when they are all killed. He is infact so strong that he defeated many of the Ohu Soldiers, even Akame loses to him but is able to cut one of his fangs and wound him and he even bites away one of Reima's legs. Though, to Gaia, Gin is the most dangrous opponent and constantly tries to kill him. However, Gin is able to weaken him enough with his battouga but, before he can finish him off, an earthquake shakes the place. Gaia takes advantage of this to kill Gin but is stopped by Reima. The two wolf leaders face themselves.

Gaia was crushed by the heavy rocks that fells down and died with his empire.