Spoiler warning! This section contains plot details about the game.
Like the Dragon, God-Dragon does not have a lore entry in Librom, but in reality the God-Dragon is actually the twin gods, Romulus and Druid, controlling Magusar, and in turn transforming him into the tyrant that the player is a prisoner of. Furthermore, if the player reads the true version of what happened before the end of the world, it's revealed that the world has constantly gone through many rebirths, known as the Eternal Recursion. After finishing the revised version of The Memories Remain, the player can choose to fight the Gods instead of Magusar.
Upon the defeat of God-Magusar, the player will comment on how Magusar has been resisting the control of the gods for a long time. However, the Twin Gods take control of Magusar's Dragon form, turning it into the almighty God-Dragon, the true final boss of the game.