From 東方 - Embodiment of Scarlet Devil (Stage 4 Boss - Patchouli Knowledge's theme)
"Again with this sick feeling...
It's a dark song, without any light or bright moments, despite its quite fast-paced nature.
It could stand to be a little less heavy, as listening to this piece could drag someone down. (Laughs)"
Afterword Shanghai Alice Correspondence vol. 1
"'Locked Girl'. A latchkey girl, if you will. It has nothing to do with Key.
She's an unhealthy girl who loves the shade.
By the way, speaking of sealed rooms... there's not much of an actual point to killing someone in one, is there?
I could probably pull off a locked-room suicide, myself."