The new origin

I'll eventually get around to making comics of all of this, but now that Conan isn't a thing anymore and it will always have been Koyuki, I'm gonna get the explanations for basic story changes out of the way now.

rather than being kidnapped for being a good specimen to turn into an army commander, like Conan was, Koyuki gets kidnapped because, being identical twins with Connie, the bad guys figure out that Connie is the moon rabbit princess reincarnation they've been looking for (so no real changes with Connie's side of events), but mistakenly nab Koyuki. Rather than be upset at the mix-up, the bad guys instead try to turn Koyuki into their cyborg sleeper agent to make kidnapping Connie easier. Since this takes place in modern day alternate-universe Japan, Kamen Rider is as established a franchise as in the real world, so it's used as inspiration for Koyuki's villainous form, though with a monstrous, insect themed head instead of the regular mask. As before, though, Koyuki is immune to mental manipulation, is broken out from inside the bad guys' base, and left on the side of a road, only this time it's in full, monstrous Rider form. Also, as a side note, they design the rider form to conceal her chest and make her look more masculine, or at least gender neutral, so that out of suit she's more easily able to hide. after all they monster people would've seen attacking didn't have a visible bust outline, so it couldn't have been this random girl nearby.

now, it's still Tewi who finds Koyuki on the side of the road and drags her to Gensokyo, but instead goes to Lili's place because she can hear Koyuki's cyborg parts whirring (and maybe there's a little bit of damage that needs patching up and exposes that this is both a living person and a machine). Tewi figures Lili or Aoi might be able to do something with who or whatever this is. Lili recognizes the Rider-esque look of Koyuki and takes her in for repairs. after fixing Koyuki up, Lili manages to finally deactivate Rider mode and watches in surprise as this humanoid bug monster turns into a rather cute looking girl. Koyuki wakes up, confused, and finds out Tewi brought her there and Lili fixed her. she thanks them, and realizes she's basically screwed now, as is her sister, and they'll need to live on the run. Lili suggests they move to Gensokyo, and Koyuki concedes that it's the best idea they have at the moment. Lili also mentions that she'd like to make some fixes to Koyuki, and alters her Rider form. her Rider head will now look more like a typical Rider helmet, but instead of insect themed, Lili's personal tastes will be on display as it'll be mildly bunny themed (it's difficult with the limitations of Walfas to go TOO bunny themed before it looks silly).

after going back home to get her sister and their things (though not finding Connie since, like I said, little if anything changes for her beyond having a sister now), Koyuki makes it back to Lili's, saying she learned her sister was spotted around where Gensokyo's entrance is, and she's going to try and find her in here, but worries about where she'll be staying from now on, Lili offering one of her home's many guest rooms, since Koyuki's tech is new, and this means that she and Aoi can study it, plus Koyuki will almost assuredly need repairs at some point, so why not just be near her new mechanic? Koyuki accepts the offer, apologizing for being a bother, and the two girls become friends. they don't actually date until a while after Koyuki finds Connie again, their interest in each other developing slowly over time. this is partly to allow for a few gags I want to do, since the necessary reactions would make no sense once Koyuki and Lili are dating.