The Justice League possessed a far deeper understanding of the Multiverse than other organizations. It had even established gatherings like the Hall of Justice, where Justice Leagues from different universes could meet, spreading their influence and allowing Heroes from different Parallel Worlds to pool their wisdom in times of crisis.
However, Earth-0 was the primary battlefield. If anyone wanted to launch a Multiversal-level grand strategy, they had to make a move against this crucial world.
This was the first world shaped by Perpetua, the template room of the Multiversal System within the current Third Dimension, as well as the origin and endpoint of all Timelines. Countless things were tied to it.
In other words, the Justice Leagues of other Parallel Universes—or equivalent organizations under other names—were basically subordinate within the larger structure.
Even so, not every Parallel Universe was under control. Within the Light Multiverse alone, the six Parallel Worlds numbered 24, 25, 27, 28, 46, and 49 could neither be investigated nor contacted for various reasons.
As for the corresponding numbered Earths within the Dark Multiverse, even less was known about them.
Earth-24 was extremely strange. It drifted up and down upon the sea level of the Blood Domain, spinning constantly as though it were shifting back and forth between reality and illusion.
The Justice League had previously believed that no life existed on that Earth. It churned the Blood Domain, and Heavenly Blood was lethally poisonous to any living creature. Even Superman needed special protection from Black Diamond to come into contact with that substance.
If there had been any other choice, Batwoman would not have wanted to take Wonder Woman to Earth -24. Simply traveling to such a Parallel World through a Boom Tube entailed enormous risk, let alone one in the Dark Multiverse.
If there were