Has "High School DxD" Light Novel ended? Has High School DxD light novel ended?
Officially, High School DxD has ended with volume 25, but it will be followed by a direct sequel titled Shin Highschool DxD (Source: afterword of Volume 25).

So the series has not really ended, as a direct sequel, Shin DxD will be covering the second half of the Azazel Cup arc. Its Volume 1 will esentially be Volume 26, just with a different label.