So, a lot of theories just got confirmed. :-) My next pet theory: The "villainess system" is not a villainess system at all, it's just the narrative engine of the game trying to resist Future!Elsa's tampering. The Reincarnated!Evie has been living in the tampered timeline from the start of the series, and we are only now getting the explanation of how the tampering that hacked a villainess route into the game that previously had none occurred in the first place. The original, untampered Elsa glitched out, fell in love with Evie, but when she died in a demon attack, Elsa went on a quest to obtain the Rings of Time and whatever weird shit happened to her irises, with enabled her to go back in the narrative and to interact with Evie, whom she has now sent even further back in the story, presumably to Elsa's own childhood, to set up a time loop where the villainess route not only exists, but can also progress past the demon attack event. In other words, this is actually the second time loop Future!Elsa facilitates: the first one created the villainess route, and the current one makes sure said route doesn't dead-end here. Maybe Current!Evie got reincarnated in the first place because it only became possible after the first loop?