The United Universes, UUniverses for short, are home to all creatures and cartoons good and evil. A long time ago, they were many different separate universes. There was a Disney Universe, a Warner Brothers/Cartoon Network Universe, a DreamWorks Universe, a Fox Universe, a Paramount/Nickelodeon Universe, a Video Game Universe, an Anime Universe, a Miramax Universe, an MGM/ Don Bluth Universe, a Hasbro Universe, and even a Heaven and Hell (Banished Realms), all bound together by cosmic magical powers brought on by terrible and ancient magical wars. These many universes never knew about one another except through rumors passed around by crazy people and fanatics. Also, there was some kind of war called the Cartoonian War, which was fought by some gods and demons as well as Chernabog, the ultimate evil known to cause mayhem in the separate universes. No mortal knew how that one turned out since most of the people that fought during the war were never there to tell the tale following the end of the war, having to separate the universes from each other for safety reasons with the use of two ancient relics called Excalibur and Lockiver (Best known as The Sword in the Stone). These two relics were hidden away to avoid being used for evil, and afterward, things went on as usual. Then one day, the relics were uncovered, and it's essence and vibe made the people of the world it was hidden on believe it had amazing powers. So when WB Arthur pulled the Sword from the Stone, the release of the sword emitted a large wave of cosmic energy that had brought the universes back together once more, allowing everyone to finally meet one another, and despite having some good interactions with each other for a few years, several crises occurred such as xenophobia, greed, and most notably the Second Cartoonian War which brought the birth of the famed Villain League. But it would be up to some unexpected heroes to balance the chaos, and bring peace to this new world at last.
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 Hell separate from the UUniverses. These two realms orbit the UUniverses in a 1,000-year rotation on opposite sides of the UUniverses.