 As Opeth 's primary songwriter and lyricist , vocalist / guitarist Mikael Åkerfeldt heads the direction of Opeth 's sound . He was influenced at a young age by the 1970s progressive rock bands Camel , P.F.M. and Gracious , and by heavy metal bands such as Iron Maiden , Slayer , Death , Black Sabbath , Deep Purple , Celtic Frost , King Diamond , Morbid Angel , Voivod , and most importantly Judas Priest . Åkerfeldt considers Sad Wings of Destiny the best metal album of all time , and notes that there was a time when he only listened to Judas Priest . Åkerfeldt sings " Here Come the Tears " by Judas Priest before most Opeth concerts while warming up . Åkerfeldt later discovered progressive rock and folk music , both of which had a profound impact on the sound of the band . 
