Simplify the following text for a Grade 8 native English-speaking person.
Original: kerfeldt was influenced at a young age by heavy metal bands such as Slayer , Death , Black Sabbath , Celtic Frost , King Diamond and Morbid Angel .
Simplified: Influenced at a young age by heavy metal bands such as Slayer , Death , Black Sabbath , Celtic Frost , King Diamond and Morbid Angel , Ã