it is a demon or spirit
Youkai is a general Japanese term for supernatural creatures in Japanese folklore.
Turns out she is a Youkai and was keeping it a secret never mind
youkai, onii, bake-mono
Princess of demons or demon princess
Chi no akuma or Chi no youkai
The cast of Youkai Watch - 2014 includes: Etsuko Kozakura as Jibanyan Tomokazu Seki as Whisper Haruka Tomatsu as Amano, Keita
"MOON SIGNAL" by Sphere
its not anything real, its part of an animation, its the academy of monsters
The cast of Otome youkai Zakuro - 2010 includes: Kana Hanazawa Yui Horie Ai Nakamura Takahiro Sakurai Aki Toyosaki
Demon = "Oni" or "Youkai" + Blade = "Katana" or "Ken"
I believe it's "Utsukushii youkai no mizu"
Demon as in "devil" is "akuma." Demon as in "evil spirit" is "youkai."