@amplified I've always thought and always forgotten to ask whether you'd agree that Shima might have drafted more backstory for the Art. In this chapter here Shirogane is taken into a trance as if something were cast on him. Could it be that the Art is supposed to possess the one who casts it and alter their mind? Not to spoil the story for first-time readers, I'd just mention here that I've come up with this thought in part because of what befell the person who had cast the Art in the past.