This is all boss themes for Touhou 6: Embodiment of Scarlet Devil to celebrate the 20th Anniversary of Touhou 6 was released on August 11,2002 and the 1st game of Touhou Windows Era
However Daiyousei and Koakuma doesn't have their own boss theme due they only being a mid-boss
All the boss themes only for remixes than the original boss themes
1st Boss - Rumia - Apparitions Stalk the Night
2nd Boss - Cirno - Beloved Tomboyish Girl
3rd Boss - Hong Meiling - Shanghai Alice of Meiji 17
4th Boss - Patchouli Knowledge - Locked Girl ~ Girl's Secret Room
5th Boss - Sakuya Izayoi - Lunar Clock ~ Luna Dial
Final Boss - Remilia Scarlet - Septette of the Dead Princess
Extra Boss - Flandre Scarlet - U.N. Owen Was Her?