"Yatagarasu" is a crow or a raven from Japanese mythology, which is believed to represent the sun. And by sun, it means Utsuho Reiuji. And by Utsuho, it means this is a remix of her theme, from Touhou Subterannean Animism.
Wait, what. I don't even.
Ah, almost forgot. Also, many thanks to Sound Bible and Team Shanghai Alice for the sound samples. (And Drake from the forum for providing it.)