One of the most memorable elements of Hideo Kojima’s Death Stranding was its standout soundtrack from the band Low Roar. Frontman Ryan Karazija recently passed away suddenly at the age of 40, and Kojima has paid tribute to the man who was instrumental in the creation of Death Stranding.

Posting on Twitter, Kojima said, “I heard the news. I can’t believe it. I don’t want to believe it.” The developer went on to say Death Stranding would not have happened without Karazija and his music.

“Without Ryan, without you and your music, Death Stranding would not have been born. Your music will live forever in this world and in me. Thank you. Rest in peace,” Kojima said.

In a post on Instagram, Low Roar confirmed that Karazija passed away recently “due to complications from pneumonia.”

“His beautiful music and lyrics, sung in his haunting voice have touched the lives of so many people all over the world, and will continue to do so. He was a kind and beautiful soul and our worlds are shattered by the loss of him. May we honor his memory through his art and hold him forever in his songs,” the band said.

A sixth Low Roar album was in the works and will be completed, despite Karazija’s passing, the band said. The group said it hopes people can respect his family’s privacy at this difficult time.

Death Stranding developer Kojima Productions reacted to Karazija’s passing as well, saying in a statement, “We are grateful that we met and honored to have worked with him. May he rest in peace.”

Death Stranding is getting a sequel, according to Norman Reedus, though the game has yet to be officially announced. In addition to this title, Kojima is developing an Xbox game.