Wiktionary
darkcore
n. (context music English) A morbid subgenre of jungle music.
Wikipedia
Darkcore
Darkcore or darkside is a music subgenre of jungle (not be confused with the more recent developments of hardcore) that became popular in the United Kingdom. It is recognized as being one of the direct precursors of the genre now known as drum and bass. Popular from late 1992 and through 1993, Darkcore was a counter movement to happy hardcore, which also evolved from breakbeat hardcore.