kurai harouiin
Azaki
kuraihana
kuraitaiyo
kuraikokoro
ダークデーモン
The phrase 'dark storm' would be 暗い嵐 (kurai arashi) in Japanese.
The Japanese do not celebrate 'our' Halloween. The have their own called o-ban. If you want to write it you would use katakana (they use this writing system for foriern words) and it would be this: ハロウィーン. If you want to say Halloween in Japanese (Nihongo), you'd just have to adapt to their sounds. So you would say : HaROwiin (wiin as in lean sound wise).
kurai mori
'kurokute utsukushii'.
Japanese is the official language of Japan, spoken by almost all of its people. The translation of dark spirit into Japanese is kurai seishin.
As it's a foreign word that hasn't really been adopted, you just say "ハロウィン" (haroueen). But keep in mind, Halloween is basically not recognized or celebrated at all in Japan.
ダークドラゴン (daaku doragon)