Headcanon: For all the Touhou jackassery, for Yuuka to be SAD is heartbreaking not only for us, but the usually jerkass population of Gensokyo.
What happened was a relatively rare sharing of information and cooperation that led to a spell-session. Everyone was there, Yukari; Eiren, Kanako, Suwako, Patchouli, etc. Others were allowed, but these did the heavy work. Their goal, transmute "chibi-Yuuka" from sunflower into a body that would not die or replace the current Yuuka.
Some had suggestions that were ignored or vetoed. Remilia suggested turning her into a vampire; Alice suggested a doll. Finally it was decided to implant a philosopher's stone into her chest. Patchouli could make partials, but through the help of several gods and reality warpers, they were able to make a complete one.
It's too bad this can't qualify for the "Heart-Breaking" pool as a standalone image. Seeing Marisa, of all people, reduced to this sobbing wreck in Alice's arms is just...
