Spectroscopy

Story
"Lady Junko...?" Returning home, Reisen looked around for her master, but she couldn't find her. Junko must have gone out. This is the tale of a different Reisen, living in a different world.

Parallel-World Senkai Junko has her own Senkai, but there is no information about it in any trustworthy historical source. Only false texts talk about it. Perhaps the value of these texts will change once some trustworthy information is found. Junko became Reisen's master long ago. They have supported each other on their journey across countless other worlds. This parallel-world Junko likes to regularly change up her Senkai, so much so that Reisen no longer gets surprised when she returns to a home that looks completely different.

Junko specially designed this Senkai to make analyzing data easier. Reisen is well aware of this because this Senkai is not only her home base of operations but also a laboratory where she spends most of her time doing exactly that. Reisen had always assumed that Junko created the multi-dimensional neural network with her senjutsu since it is such an incredibly effective data-gathering tool. However, any data gathered in this Senkai becomes tainted by maddening resentment. This is because the Senkai itself was formed from highly purified madness. Only Reisen, with her madness-manipulating ability, could possibly perform this intellectually demanding task in such a harsh environment.

Reisen found that the multi-dimensional neural network wasn't all that different from the moon rabbits' telepathic network. The process of delving through it and analyzing its data is pretty much the same. While Junko was away, Reisen decided to investigate something that had always bothered her. She wanted to know what the multi-dimensional neural network actually is. What she discovered is that the network existed long before Junko started using it as a tool to gather data and that the strands of temperament stretching across multiple universes and converging at nodes of power seem eerily similar to a giant creature's disembodied nervous system.

"Is the multi-dimensional neural network the remains of an incredibly ancient and impossibly large organism...?" "Well done, Reisen. I knew you'd figure it out." Apparently, Junko was planning to tell Reisen about this soon, even if she hadn't investigated it herself.