This is Patchouli Knowledge's theme from Touhou 6: the Embodiment of Scarlet Devil
Ah, this brings back wonderful memories of IOSYS... anybody remember Unlocked Girl? I must go and find that again.
ZUN is so brilliant at creating beautiful pieces, it fits Patchouli so well. Here's a girl that barely sees the light of day, and is cursed by two dreadful ailments, which physically diminish her to the strength of a 10 year old. However, what she lacks in power, she makes up in magic, having intense magical strength over the elements. She really is a classic magician.
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