- The titular song of Singin' in the Rain shows up a few times, the second time as a definite A Clockwork Orange shout out. But the first time is different. That's just Shiki and Mikiya standing together with both of them truly happy. Now, in the film the context of the song is this; of a cynic who's so madly in love that everything is brighter, so much that he can sing and dance in the rain. Now, Shiki's personality and her view on life is definitely cynical. And then Mikiya walks in and makes her whole world brighter. If you put that logic to that scene, it becomes a million times more heartwarming.
- The Mirai Fukuuin OVA continues this with SHIKI humming it during his last appearance after being told that his Dream (aka Mikiya) will go on by Mother Mifune. Appropriately, this is with rain falling down.
- The title of the work ("Kara no Kyokai") refers to Shiki, specifically, to her physical body, which represents the outer boundary confining the proto-substance of the Void/Emptiness for as long as she lives. The "Garden of Sinners" subtitle refers to the cavalcade of various evil creatures (humans and otherwise) seen throughout the series, one of whom is Shiki.
- The Taijitu in the seventh movienote : When Mikiya visits Shiki's apartment, he receives a call from her on her own phone... coming from his house (to which Shiki demanded a key in chapter 5). So not only are the contents of their conversation important, but the context is also highly symbolic and represents how deeply intertwined and basically inseparable Shiki and Mikiya's (yin and yang, respectively) existences have become at that point. It also foreshadows that even if he is never able to forgive Shiki for becoming a murderer, Mikiya will also never be able to abandon her, no matter what she does.
- Maaya Sakamoto's casting as Shiki is one in itself. To be perfectly honest, whenever Sakamoto is cast as a "hardass" character the results are...mixed, to say the least. This is best exemplified in end of the first chapter where Shiki tells Mikiya to "Eat the damn [ice cream]". His response? To go "What?" because it just sounded so awkward and forced for Shiki. However, Shiki is doing it on purpose because she's trying to compensate for the loss of the other SHIKI thus leading to her sounding clumsy whenever she's forcing herself to play "tuff chick" (a role she KNOWS of, but doesn't quite get the nuances) instead of just acting naturally. It helps establish the sense of disconnect Shiki has from the loss of her other personality.
- Touko's decision to enchant Shiki's replacement arm with the ability to grab incorporeal beings comes seemingly out of the blue — until you remember that in terms of chronology, it's been a few weeks since Hollow Shrine, where Touko witnessed first-hand that ghosts of all kinds are attracted to Shiki's "hollow" body like flies to honey. It only makes sense that she would give Shiki an upgrade to allow her to dispatch ghosts in ways more convenient than letting them possess her and stabbing herself in the chest.
Fridge / Kara no Kyoukai