Being a All Mulitverse
Since it's also an All Mulitverse in Dimension-50, Earth has other things very similar to other Mulitverses. Most notably be the Halo Mulitverse, where the UNSC exists alongside the Alpha Legion, and also an Mass Effect technology of the Protheans. There are also other small ones within it, such as Clannad, and even Corpse Party.
Earth still had World War I and World War II from the same causes, except the Fabula Kingdom was in it, and is allied to the United States, and the Alpha Legion was also in it. Arthur Pendragon also fought both of the wars.