Fate/stay night: Heaven’s Feel II. Lost Butterfly

After Saber vanishes, Shirou Emiya finds himself effectively eliminated from the Holy Grail War, yet he remains determined to keep fighting. He resolves to press on as a would-be Magus, continuing to act in the war despite the setback. This marks the start of a more precarious path for him and his allies.

Shirou returns from a meeting with Rin Tohsaka to discover Sakura has been abducted by her brother Shinji. He confronts Shinji, and Sakura pleads for everyone to stop the confrontation. Rider, answering Sakura’s call, reveals that Sakura is her true Master, reframing the danger in the battle.

Archer and Rin attack Sakura, but Rider defends her and uses her gaze to turn their attackers to stone. In the process, Rider’s true identity as Medusa is revealed to everyone. The moment deepens the crisis as trusted allies confront Sakura.

During the chaos, Shirou is hurt and loses consciousness. Sakura’s overwhelming grief drives her to injure herself, an act that pushes Rider to intervene and halt the escalation. The characters’ bonds are strained as the true danger grows closer.

Shirou reawakens inside Fuyuki Church to find Kirei Kotomine operating on Sakura. Kotomine explains that Sakura’s body is infested by Zōken Matou’s Crest Worms, which feed on her mana by arousing her. He also reveals Sakura and Rin are blood sisters, and that Sakura was adopted by the Matou family.

Despite the grim revelations, Shirou promises to protect Sakura, even at the cost of his own ideals, which leads Rin to back off. Sakura returns to the Emiya household accompanied by Rider, and the Crest Worms begin to influence her more strongly, making her behavior increasingly erratic.

Shirou and Rin seek Illyasviel von Einzbern to form an alliance, but she is fighting Zōken and the shadow. The confrontation unleashes the corrupted Saber to subdue Berserker, while Archer drives off Assassin. The shadow mortally wounds Archer, severing Shirou’s left arm in the process, and Archer selflessly transplants his arm to Shirou to save him.

With their Servants lost, Rin and Illya move into the Emiya household to plan next steps and help Shirou adjust to his newly transplanted arm, which is sealed with a holy cloth to manage its power. The family dynamics shift as they begin to rebuild around Shirou’s altered body.

As Rin grows closer to Shirou, Sakura becomes increasingly jealous and questions whether Shirou loves her romantically. Shirou affirms his feelings, which leads to a complicated development as he and Rin engage in intimate relations. The love triangle intensifies the emotional stakes for everyone involved.

One night, Sakura sleepwalks through the city and kills several people. Gilgamesh confronts her, but the shadow devours the King of Heroes. Sakura returns home, and Shirou begins to suspect that the shadow itself is emerging from Sakura.

Illyasviel reveals that Sakura has become the vessel for the Holy Grail and does not have long to live. This revelation heightens the sense of urgency and despair surrounding Sakura’s condition. The Emiya household braces for the looming catastrophe.

Zōken confronts Shirou, admitting the shadow is a fragment of the Holy Grail placed inside Sakura ten years ago. He warns that stopping it may require sacrificing Sakura, a prospect Shirou cannot bear to face. The moral dilemma drives a wedge between his duties and his feelings.

Sakura, believing herself a burden to Shirou, orders Rider to protect him and departs for the Matō estate. Shinji attempts to rape Sakura, blaming her for his failures as a magus. In a desperate, violent confrontation, Sakura panics and kills Shinji, but the shadow fuses into her body and corrupts her completely.