Although it is called a Universe, the Omega Universe is only one world, not a planet, a star, or even a galaxy. The world was called Castra Obis, unimaginably vast and unaccessible by higher being like the Twelve. In the Era of Beginning, some speculated this world wasn't the handiwork of the Twelve but something else. Others explained how Castra Obis came into existence through a series of natural and scientific events. Whatever the truth was, it can be said, for certain, that the Omega Universe was never fully explored due to its absurd size.
Zodiak and Forne, who recently became companions, traveled around 15% of Castra Obis in around sixty years. They've encountered countless people and became much stronger, especially the once-young Forne, who grew up and became a middle-aged man. While Zodiak chose an unorthodox route to strengthen himself, Forne started cultivation right after obtaining Destruction Magic.