"Realm of Light" can be seen in the background of this card's artwork. It is partially destroyed, so it is likely after the effects of "Light of Destruction", or possibly it was the destructive force of this card's own effect.
This monster's effect may refer to the concept of Judgment Day. In said concept, the world is destroyed by some sort of deity, while "Judgment Dragon" destroys all cards on the field except for itself. The presence of the word "Judgment" in this card's name further reinforces this connection.