One thing I've always wondered is the extent to which Sakura's
appetite as the Shadow was tied to her resentment towards Rin
and her possessiveness of Shirou. While I realize that Zouken's
implantation of crest worms and Grail Shards in Sakura is what
caused her to become a magic-eating monster in the first place,
I can't help but notice that her appetite greatly increased after
the events of Day 9 (I.e: overhearing that Rin planned to kill her
and having sex with Shirou). For the first 9 days of the route,
Sakura just ate humans' energy while leaving their bodies intact.
However, after overhearing after Day 9, she not only eats Shirou's
arm but ultimately ends up devouring most of Fuyuki. Even Zouken
expressed surprise at the sudden increase in Sakura's appetite while
walking around the city with Assassin during one of the interludes
so it obviously wasn't a part of his plan. Is there a direct link between
Sakura's emotional state and her hunger as the Shadow or is her
devouring of humans after the events of Day 9 just a coincidence?