Vocal arrangement of Remilia Scarlet’s theme, aki oujo no tame no seputetto. This track can be found in Crest’s first touhou album [流月抄 ～ Moon over Mind] which was released in R7 with Yurika as the vocalist(you might know her better as hana-tan at NICO NICO DOUGA). Enough said, listen to the song and you will understand. My music player just randomed into this song and I got a sudden urge to share it.
Crest’s website: http://crest-music.com/