Rob Holliday is half of the band Sulpher, having duties as a lyricist, guitarist and lead vocals. They have released one album titled Spray, with two singles for the tracks "One of Us" and "You Ruined Everything", and currently have a second album in production. Sulpher also includes Monti (Curve, Cocteau Twins, Gang of Four, The Jesus and Mary Chain) as producer, programmer and drummer and Tim Mud as live guitarist. Holliday is currently the live guitarist for Gary Numan and live guitarist and live bassist for The Prodigy, and also played live guitars and bass for Marilyn Manson during the Rape of the World tour. Holliday did not contribute to the writing or recording of the band's album Eat Me, Drink Me, released in 2007.
Although many people believed Rob to be a temporary member, Manson stated on an interview entitled 'Everyone Will Suffer Now' on the Heirophant[clarification needed] that this is not the case, and that Holliday will stay as a permanent member of the band. It has recently been confirmed that Holliday will be playing live guitars for The Prodigy on their 2008 tour. This leaves unclear if (and to which degree) he has contributed to Manson's upcoming album The High End of Low, as was the case with the band's former guitarists (with the exception of Mark Chaussee).