Deathgyunos is a major antagonist in Final Fantasy: Legend of the Crystals and is the God of Oblivion. He was reborn by Ra Devil 200 years after the events of Final Fantasy V, using the powers of the four Elemental Crystals. Deathgyunos's goal is to destroy Planet R, and possibly the entire universe.
Deathgyunos is a giant grotesque mass of organs which inhabit a large, metal body created by Ra Devil to house the god. It possesses Ra Devil himself and mutates him into a mass of flesh wired into the machine body.
Being the God of Oblivion, Deathgyunos is primarily driven by a desire to destroy everything, beginning with Planet R. He possesses immense power and can withstand most attacks due to being powered by the four Elemental Crystals. The knowledge of the Crystals which Ra Devil obtained from Cid's brain resides within Deathgyunos.
Deathgyunos appears when Ra Devil combines the power of the four Crystals to absorb a mysterious cosmic energy and transform into the god himself. He is mentioned earlier by both Mid, who warns Prettz of the coming danger, and Queen Lenna, who tasks the heroes with regaining the Crystals and defeating Ra Devil before Deathgyunos returns to destroy everything. The disappearance of the Crystals and Hassam's warning that something horrible is approaching foreshadow the return of the god.
When the heroes reach the Black Moon they witness Ra Devil's transformation. Valkus orders the Iron Wings to attack Deathgyunos, and the heroes engage in a mid-air battle with him. Deathgyunos is defeated and crumbles before the heroes but is not truly dead, for soon it rises from the rubble and launches another attack. Mid buys some time for the heroes to get to safety, but to no avail. Deathgyunos continues his advance and almost kills Prettz. Valkus and Rouge fend him off, until the heroes come face to face with the god atop a crumbling structure.
The heroes face off against Deathgyunos, and after Rouge, Prettz and Valkus are knocked down by his powerful laser, Linaly uses her magic to destroy Deathgyunos. Deathgyunos falls before them, seemingly defeated. Yet Ra Devil escapes destruction and charges at the heroes. Prettz evades his attacks and slices Ra Devil in half.