Well then.
Originally we were thinking of having this story be all but centered to take place on Chralmede, with some fun "bermuda-triangle" stuff to be found, maybe a space-ship or two, maybe an orbital station etc.
The two main reasons for this are the following:
The world of Chralmede, while technologically advanced, had not yet advanced into space, a few reasons to this may be revealed in the story.
Bringing their henchmen into this world taxes the villains, or rather the one doing the actual bringing. For even though the dimensional barriers in this multiverse are leaking with a 90 degree slope into Chralmede, it still takes an enormous amount of energy to manage it. And in this case it isn't harder to transport living things but rather the amount, as every little thing scrape the dimensional barriers around this universe thinner in the places that aren't already ripped apart.
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If you absolutely want to have a spacial armada with the power to absentmindedly destroy a planet at your command it would even to begin with not pose as much of a threat as one would think. Because this is a multiversal story, and as such there are more than science to be afraid of. Apart from the possible relical structures that were initially out on Chralmede for the heroes to find, and the less physical threats towards such an armada (as it would be one of the first things the heroes aim to destroy). There would also appear the obvious case of space-ships being built to fly up and fight against it, hell it might even turn interesting with a few space-battles.
And that is not to mention how all the villains would react to the imperial might. Even if Vader happened to be one of the five, who are supposed to be in possession of god-like might, though preferably individual such as opposed to the might of their armies.
The idea I suggest is one of beginning construction on something big, and using it as a perfect plot-line for the heroes to have a target to destroy, and for the villains to defend.
