Songfacts®:

• This is one of two tracks Sum 41 frontman Dereck Whibley wrote with his friend Mike Green for Order In Decline ("A Death in the Family" is the other one). Green has also penned songs for the likes of All Time Low ("Ground Control") and 5 Seconds of Summer ("Permanent Vacation").
• Whibley originally went over to Green's place just to catch up with him, but they ended up writing "Out for Blood." He told HMV.com: "I started playing him a riff and he had a few ideas, and suddenly there was a song being written."
• This was chosen as Order In Decline's lead single, as it ticked all the boxes of what the album is about. Whibley explained to Kerrang:
  
  "There's some heavy stuff in there, some crazy guitar solo stuff, there's different riffs, it's catchy, it has a melodic chorus, and to me it sounds very Sum 41. But it also has some different stuff that we haven't really done before. It leans on the heavier side of us a little bit more than we have in the past."
• Whibley told Kerrang that the band didn't set out to deliver any particular message with "Out For Blood." Rather, they wanted to convey everything that a Sum 41 show is about. "We all go through bulls--t in our lives, but we can release our aggression through music, rather than resorting to the hatred you see in the world at the moment," he explained. "The video references the film Fight Club in that way, but we refer to it as 'Mosh Club.'"
• The song landed Sum 41 in the Top 20 of a Billboard airplay chart for the first time since "Pieces" peaked at #14 on Alternative Songs in 2005. As well as reaching the top 20 of the Mainstream Rock tally, "Out for Blood" also hit #1 on SiriusXM's Octane channel.