There are multiple words for different types of 'demons' in Japanese. I'll go with 'akuma'. 悪魔ファイター /a ku ma faa i taa/ or 悪魔戦闘者 /a ku ma sen tou sha/ could be literal translations of that phrase.
demon blade in Japanese is akuma no tsubasa
地獄の悪魔獣 Jigoku no akuma-juu
ma o
The Japanese word for 'Demon World' is 鬼の世界.
It's a general Japanese term for demon lord, powerfull demon, or large demon.
Akuma. it means devil or demon.
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.
Demon = "Oni" or "Youkai" + Blade = "Katana" or "Ken"
'Beautiful demon' would translate to 美しい鬼 (utsukushii oni) in Japanese.
'Demon girl' would be translated as鬼ã®å°‘女 (oni no shoujo) in Japanese.
"Water" is mizu 水 and "demon" is "akuma" 悪魔。
Hanyo.