 In reference to their sole studio album, TeethOfTheDevine.com said that "Where most bands in this space use death and thrash metal devices to create a sense of heaviness missing in traditional hardcore, Arma Angelus’ thick, angular attack comes from a rock and roll sense of composition that’s every bit as heavy as their metal-infused counterparts.True, elements of Where Sleeplessness is Rest from Nightmares do delve into death metal territory (vocals, tuning), the majority of Arma Angelus’ material pummels to the tune of catchy, head-bashing song structure.