Seraph of the End: Guren Ichinose: Catastrophe at Sixteen

Story

The apocalypse is not only near, but a certainty. Set before the event and the aftermath detailed by the hit manga, this stand-alone prequel light novel series chronicles the inexorable approach of the reign of vampires. Witness the trials of Guren Ichinose, who must hide his true strength even as he is trampled on at an academy for the insufferably privileged.

Synopsis via AniList (English).