All I could think while reading this was the conversation that Marisa and Reimu had before the final battle in Concealed The Conclusion.
M:"Hey, Reimu, is everything really going to disappear? Is there nothing I can do even now?"
R:"I have always said this from a long time ago that there is nothing as useless as effort. Thank you for dealing with my selfishness until now. And I'm sorry."
M:"... So this is going to be the end soon... Don't you have something you want to say? If there's no way to avoid it, and this is truly fate, then having you as my final dueling partner must also be fate. To bet on Gensokyo's eternal fate, I propose a final Danmaku duel!"
R:"A battle to decide the eternal struggle... I accept!"
R:"Gensokyo is MINE, I will not hand it over to you!"
M:"Gensokyo isn't just YOURS, you can't take it away!"