High School DxD DX.4 is a compilation that will consist of new short stories and is considered as Volume 23.5. It is the fourth of the DX. series.
- [Imperial Purpure] Team VS [Spear of the Heavenly Emperor] Team ---The Proof of a Hero---
- Power.1 The Indestructible Great King
- Power.2 The Hero and the Youths
- Power.3 A Mad Feast of Power and Technique Begins
- Power MAX vs Technic MAX The Lion King's Iron Fist and the Hero's Holy Spear
- [Sekiryuutei of Blazing Truth] Team VS [Sona Sitri] Team ---Stronger Than That Time, Further Than Now---
- Line.1 The Various Differences From Last Year
- Line.2 The Student Council's Secret
- Line.3 The Basis of the Dream
- Line.4 The Revenge Match Begins!
- Line.5 Field break
- Line.Maximum vs Life.Maximum Dragon King (Idiot) and Dragon Emperor (Idiot)
- Final Line. The Student Council and Leviathan
- New Line.
- This is the first light novel that features Elmenhilde Karnstein on the cover.