Earth Dragon Gakia is the eldest and strongest of the Earth Dragons in the Great Elroe Labyrinth. He resides on the Bottom Stratum. When Ariel investigated the death of the Queen Taratect that was killed in the Bottom Stratum, Gakia, the Guardian of the Bottom Stratum, confronted her with knowledge about Kumoko, stating that they must make way for the new ones. Ariel was already enraged beyond reason and attacked them, promising to devour them.
Gakia was killed by Ariel, along with the rest of the Earth Dragons of the Bottom Stratum, in the battle that ensued. It was not an easy battle, despite the huge difference in status and abilities between Ariel and the Earth Dragons. The dragons occupied Ariel for a long time, enough for Kumoko to be revered as the Divine Beast in Sariella and a war to break out between Ohts and Sariella.
Gakia and the rest of the earth dragons' corpses where given by Güliedistodiez to Kumoko as a gift and reward for surviving Ariel's surprise attack for interfering with Kumoko against D's wishes. Their corpses where used as sustenance to fuel Kumoko's final evolution, the Arachne,however in the anime, the evolution was only necessary when Ariel had just killed Gakia with the help of one of Kumoko's parallel minds, as Ariel's merger with one of Kumoko's parallel minds was one of the factors for Kumoko to evolve into Arachne.