Gloomy part of the legend is malicious (6)
I believe the answer is:
dismal
'gloomy' is the definition.
(I know that gloomy can be written as dismal)
'part of the legend is malicious' is the wordplay.
'part of' says the answer is hidden in the clue.
'DISMAL' is hidden within 'legend is malicious'.
(Other definitions for dismal that I've seen before include "Gloomy and depressing like winter weather" , "Sad, gloomy" , "Gloomy, bleak" , "Lugubrious" , "Sad and dreary" .)