Why are they a pair? Is there any evidence where the two of them were together? Also, most of the videos of Mito are not translated, so that's why I don't watch most of her videos. Yes, I know she streams a lot.
The whole story more or less revolves around Akane and Rikka's relationship, and the reason Akane gets saved in the end is because of how Rikka feelings about her. Rikka's one wish is that she can be with Akane forever.
Though, Akane leaves because she has to learn to face the real world on her own and get over her crippling depression. But, if you listen to the voice dramas which aired along side the anime, Akane actually comes back to be with Rikka.
Best spoiler I've read
Is that even true? I thought it was just a male protagonist and full of mecha action. Not with Rikka and Akane. I mean, I still don't see any evidence of how those two are paired up this way.