In 2004, Isis issued Live I 09.23.03, the first in a series of concert recordings that the band would release from its archives. Oceanic became the band's breakthrough record, receiving positive reviews upon its release in 2002. Dubbed SGNL>05, the EP expanded the conceptual and musical threads of Celestial, complete with a remix by one of the band's heroes, Godflesh's electronic wizard Justin Broadrick. The band toured relentlessly in its support with the likes of the Dillinger Escape Plan, Candiria, and Burn It Down, releasing a follow-up of material from the Celestial sessions through Neurosis' own Neurot Recordings in 2001. In 2000, Isis produced their masterwork, the Celestial opus, which built upon the promise of the EP releases while expanding the band's scope to include more warmth and melody than its decidedly brutal predecessors. Randall exited the group shortly thereafter and was replaced by Cliff Meyer, and Isis subsequently toured with Cave In that summer before supporting Neurosis - who had become admirers of the group - that winter. In 1999, Isis released an EP titled The Red Sea through Second Nature on both 8" vinyl and CD. Former Cast Iron Hike guitarist Mike Gallagher joined the lineup in time for a tour with Converge and Cavity, just as Mereshuk exited and was replaced by Agorophobic Nosebleed's Jay Randall. With noisemaker Chris Mereshuk on keyboards/samples and minus Larson, the band recorded the The Mosquito Control EP at God City Studios in 1998, establishing Isis as a band with artistic vision and conceptual foresight. The band recorded a demo that year with guitarist Randy Larson, garnering the attention of Escape Artist Records.
It was the union of Turner with bassist Jeff Caxide and powerhouse drummer Aaron Harris that formed the core of the Isis project in 1997. The band was formed by Hydra Head Records owner Aaron Turner, who was hoping to combine the minimalism of Earth and the Melvins with the experimentalism of Godflesh, backed by the depth and power of the band's most obvious musical counterpart, Neurosis.
Not so much a band per se as a musical collective, the members of the Boston-based quintet layer their compositions with feedback, power chords, quiet/loud dynamics, and vocals that are sometimes shouted, frequently screamed, and occasionally sung. Although rooted in heavy metal and the punk/hardcore aesthetic, Isis' music relies just as heavily on ambience, atmosphere, and tone as it does complexity and aggression.