astral buddy

とある科学の超電磁砲外伝 アストラル・バディ (Toaru Kagaku no Railgun Gaiden: Astral Buddy)

A spin-off manga of ToAru Kagaku no Railgun written by Kamachi Kazuma and drawn by Nogi Yasuhito, starring Hokaze Junko and other Tokiwadai students and taking place in Tokiwadai Middle School.
Finished, has an ongoing sequel - ToAru Kagaku no Mental Out.

This tag implicates toaru_kagaku_no_railgun (learn more).