NERU: Bugei Dougyou

Meet Neruma Isami, more commonly known as Neru. His martial artist grandfather left behind a book which serves as his only guide for his solitary training. Neru's about to finish middle school and is totally unsure about his future. But everything changes when meets the mysterious martial artist Akebi Haiba. She leads Neru to a high school where the toughest fighters have assembled. This martial arts high school action series now begins!

(Source: MANGA Plus)

Note: Volume 3 includes the 4-chapter miniseries that this manga is based on