Movie
Description
Yûsuke Ninomiya, known as Yû, survived a plane crash in infancy that claimed his parents' lives and left him paralyzed, confining him to a wheelchair. He grew up in a Tokyo hospital, encountering an old man who professed the ability to traverse worlds and wield magic. Later adopted by a flower shop owner, Yû lived alongside adoptive sister Saki Mishima.

As a child, Yû intervened when Haruto Ichihara (Haru) faced a dog attack, diverting the animal by throwing a stone at himself so both could escape. This act forged an unbreakable bond. In high school, Yû aided Haru's basketball strategies, while both harbored feelings for classmate Kotona Takashina. Haru ultimately dated her. The trio spent time together, though Yû sometimes faced exclusion due to inaccessible locations.

Yû received a panicked call from Kotona being chased. He found her just as an assailant stabbed her with a mystical dagger. When Haru tried to carry her away, all three narrowly avoided a traffic accident and were transported to Ni no Kuni, a parallel fantasy world. There, Yû gained the ability to walk. He and Haru discovered Princess Astrid of Evermore, who resembled Kotona and bore identical curse marks. Yû removed a manifested dagger from Astrid, curing her.

Yû learned Kotona's life in the real world was linked to Astrid's in Ni no Kuni. Upon Kotona's terminal tumor diagnosis, Haru resolved to kill Astrid to save her. Yû opposed this plan, refusing to sacrifice Astrid. After confronting the assassin again, Yû was captured in Ni no Kuni and forced to battle Haru during the Black Banner army's invasion. Their duel transported them back to the real world.

Yû deduced Saki's life was linked to Bertha Roam, a captured knight in Ni no Kuni. He and Haru rescued Saki from the assassin, who transformed into a monster. Returning to Ni no Kuni, they exposed the true antagonist: Crown Prince Sedulus Astrum (disguised as minister Gnauss Wisden). In the final confrontation, Yû intercepted an attack meant for Astrid, suffering critical wounds. An old man (revealed as Oliver from another timeline) declared Yû a true hero. Empowered by the Divine Avnaron and the sword Mornstar, Yû helped defeat Sedulus.

The resolution revealed Yû originated from Ni no Kuni, not the real world; his presence in Haru's world was temporary to save Haru from the dog attack years prior. After the battle, Yû chose to remain in Ni no Kuni as Prince of Evermore, entering a relationship with Astrid. Those in the real world forgot his existence, except Haru, who retained their shared memories. Yû's personality is defined by strategic thinking, loyalty, and moral conviction, often contrasting with Haru's impulsiveness. He consistently demonstrates courage and protective instincts, refusing to sacrifice others despite personal stakes.