Complex sentence: This album saw a reunion with former drummer Gene Hoglan (who previously appeared on the band's 1997 album "Demonic"); during the recording, he filled in for Paul Bostaph due to his "serious injury".
Split into simpler sentences: This album saw a reunion with Gene Hoglan, who played drums on the band's 1997 album "Demonic". During the recording, Hoglan filled in for Paul Bostaph due to his "serious injury".