Sylosis is a British metalcore band formed in Reading, Berkshire in 2000 by guitarist Josh Middleton and bassist Carl Parnell. The band blends thrash metal with melodic death metal and metalcore influences, creating a distinctive sound that evolved across their discography. After signing to Nuclear Blast Records in 2007, they released their debut album Conclusion of an Age in 2008. Subsequent albums including Edge of the Earth (2011) and Monolith (2012) established their presence in the metal scene. Following a hiatus in the late 2010s due to Middleton's involvement with Architects, the band reunited in 2019 and released Cycle of Suffering in 2020. Middleton remains the sole original member, with the current lineup featuring drummer Ali Richardson and bassist Conor Marshall.