Movie
Description
Jun Tendo is a shy, seemingly weak middle school student branded with a distinctive birthmark on his left shoulder. This mark confirms his direct descent from the Magatama clan and grants him the unique power to awaken and command the mythical eight-headed dragon, Yamata no Orochi, making it his servant and source of strength.

His family history is marked by tragedy and valor; his father, a teacher, died heroically saving a boy at a railway crossing. This legacy of sacrifice deeply influences Jun's developing sense of responsibility and moral compass.

Jun finds himself involuntarily hurled 1200 years into Japan's past, arriving in the Heian era. There, he is declared a prophesied savior destined to end a war between humans and Oni. Overwhelmed and confused by this role, his initial weakness makes him a target for bullying. He flees Oni attacks, seeking sanctuary in a temple.

His journey centers on a profound moral conflict. After summoning Orochi to protect allies like the swordsman Raiko Minamoto, an Oni named Mizuha reveals her people are displaced humans wearing masks, driven from their homeland by colonizing human nobles. This revelation forces Jun to question the war's morality, recognizing valid grievances on both sides. He refuses immediate allegiance to either faction, seeking a path to peace without further bloodshed.

Jun's control over Orochi evolves; initially requiring an incantation, he later triggers the dragon through raw emotion, like screaming Raiko's name in peril. Orochi becomes an extension of his will, achieving its ultimate form during the final confrontation.

The climax pits Jun against the corrupt monk Gen'un, who manipulates the conflict for godlike power. Jun witnesses Gen'un betray and murder a temple councillor, then transform Raiko and others into mind-controlled entities. Empowered by merging a gem containing his true power with a dagger from Raiko's past, Jun forges a sword. He leads a unified effort against Gen'un, culminating in Orochi's transformation and victory.

With the conflict resolved, Jun returns to his original timeline. His experiences in the past forge newfound confidence and resolve, enabling him to move forward.