Ahahaha, holy crap. Youmu's face here is priceless. (Though I suppose I had to have read this first.)
Anyway, creepy story. Awesome premise, but still not something I can fully accept. I gotta admit that I've never understood Sakuya's determination to remain human. Beneath the happy smiles through to the end of this story I can still only see the undercurrent of Remilia's pain.
It's true that immortality, or a placid eternity without conflict, is like a denial of life. To have Sakuya become a vampire and live by Remilia's side forever would admittedly feel somehow like a betrayal of their current bond. I feel like 'loyalty' is a feeling inspired by embodied greatness -- constant evolution and change. For a relationship of loyalty to be bound by eternal life would somehow smother it and displace it with a weaker, more dependent feeling.
However, the fact remains that compared to a devil's a human's lifespan is just too brutally short. Sakuya, in her human prime, can't probably live for more than 20 years. This against the hundreds or thousands through which Remilia will persist as a vampire. I can't really see Remilia as eternal in the sense of the true immortals of Touhou in the first place, so if Remilia's life will burn out at some point anyway, I can't see why they couldn't spend more of their time together.
Ahhh, I guess what I'm in the mood for now is some "when Sakuya dies" stories. I want a taste of some of that raw pain and emotion instead of the lukewarm acceptance painted at this point in the story. Maybe some artist will have come up with a better idea than really just letting Sakuya die as a human. This is probably the first doujin to have truly reached into me about the cast of the Scarlet Devil Mansion.