黒紐 (kuroi himo) means "black string." It isn't possible to use the actual word for "dark" 暗い (kurai) without referring to ambient lighting.
Azaki
kuraihana
kuraikokoro
kuraitaiyo
ダークデーモン
The phrase 'dark storm' would be 暗い嵐 (kurai arashi) in Japanese.
kurai mori
kurai harouiin
'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.
ダークドラゴン (daaku doragon)
You don't.