Slayers Special is a spin-off prequel series of 30 novels published from 1991 to 2008. Each consisting of one-shot stories (sometimes, two-chapter stories) chronicling the exploits of Lina Inverse and Naga the Serpent before the events in Slayers.

(from Amazon)Jindai High School was a relatively safe place, right up until Sousuke Sagaka transferred there. A total nut, he wreaks havoc on the school's student body and gets into a world of trouble with the teachers! But there's more to Sousuke than me