

Īvenged Sevenfold's material spans multiple genres and has evolved over the band's entire career. However, on February 17, 2010, Avenged Sevenfold stated that they had entered the studio, along with now-former Dream Theater drummer Mike Portnoy, to drum for the record, in place of the Rev.

The band members admitted in a number of interviews that they considered disbanding at this point of time. Whether or not he will be joining the band on a permanent basis has not been decided yet. On January 20, 2011, Avenged Sevenfold announced via Facebook that former Confide drummer Arin Ilejay will tour with them starting this year. They played for US Soldiers at Camp Adder, Camp Beuhring, and Balad Air Base. However, Portnoy did travel with the band overseas in December 2010 for three shows in Iraq and Kuwait sponsored by the USO. After finishing recording, in December, Portnoy and the band posted simultaneous statements on their websites stating that he will not be their replacement for The Rev. Nightmare beat sales projections easily, debuting at number one on the Billboard 200 with sales of 163,000 units in its first week. It met with mixed to positive reviews from music critics but was well received by the fans. Mixing for the album had been completed in New York City, and Nightmare was finally released worldwide on July 27, 2010. A preview for the song was released on on, but was removed soon after for unknown reasons. The single "Nightmare" was digitally released on May 18, 2010.
