'Beautiful demon' would translate to 美ã—ã„鬼 (utsukushii oni) in Japanese.
demon blade in Japanese is akuma no tsubasa
ma o
ダークデーモン
ma o
Hi no akuma
aoi akuma
Furasshu no akuma
youkai, onii, bake-mono
Akuma no Tousen :D
鬼 /o ni/ is a good Japanese equivalent for what you are looking for.
The japanese word of song is "uta"and beautifull is"ii"...so you can say it in japanese..."ii uta"
Ookami means wolf in Japanese and yasha means demon in Japanese. Ookamiyasha means wolf demon in Japanese and yasha ookami means demon wolf in Japanese.