Simplify the following text for a Grade 8 native English-speaking person.
Original: Viking metal is a lyrical theme ( falsely regarded as a subgenre ) of heavy metal music characterized by its galloping pace , keyboard-rich anthemic sound , bleakness and dramatic emphasis on Norse mythology , Norse paganism , and the Viking Age . In most cases the viking-themed metal consists of any combination of black and folk metal .
Simplified: Viking metal is a heavy metal music subgenre inspired by Norse mythology .