Each universe is not like the one that we commonly associate with, being vast and consisting of several galaxies and interstellar oddities. Instead, each of these universes are 50% smaller, and consist of a powerful cosmic heart that not only forms a galaxy-like formation called a 'unigalax', but they are also compatible with each other, able to attract each other. But when it was decided by the fighters of the First Cartoonian War that the universes should be kept apart for safety measures, they created the universes' compatibility's lock and key, Excalibur and Lockiver. When the sword is locked inside, it nullifies the compatibility and repels the universes. When it is released, the compatibility is restored and the universes merge back together.
The unigalaxes function the same way that galaxies do. They contain over sextillions of stars and planets, each coming in different shapes and sizes. The universes' heart is what forms these formations and even functions like an orbit for all of the stars and planets, completing a rotation every 1,000 years. Though worlds do exist in the heart, but most of them contain magical properties and occasionally experiencing several anomalies. Galaxies can exist inside these unigalaxes, sharing the same orbit as all other objects in the universes.
The cores are able to merge with each other through cosmic chains that makes each universe connect like a necklace, and inside this formation, there exists a massive area as big as our universe called the Boundary Cluster, where no stars, worlds, galaxies, or asteroids exist. This cluster is accessible through wormholes that come out from the side that the universe is facing it. When the universes are separate, this cluster divides itself and merges with each separate universe until it should re-merge again. In the center of this cluster is where a Boundary Generator exists to keep certain realms like Heaven and the Banished Realms separate from the UUniverses. These two realms orbit the UUniverses in a 1,000-year rotation on opposite sides of the UUniverses.