Light Novel Volume 0 is a special volume that is included in blu-ray disks of High School DxD HERO. There are events which happened few hundred years prior to Light Novel Volume 1 and how Sirzechs and his friends became the new Four Great Satans, how they took part in civil war of the Underworld against the the descendants of the original Satans.
- Chapter 1. Crimson-haired prince of destruction
- Chapter 2. Future of devils
- Chapter 3. Those who surpass the satans
- Chapter 4. The birth of Sirzechs Lucifer and Rias Gremory
- At the moment it's the only volume that has official English translation. The translation done by FUNimation Entertainment.