Shimai Ningyou

Based on the game by Nine Heads. In a world where forbidden emotions simmer beneath the surface, a devoted brother finds himself consumed by an overwhelming love for his sister. As she battles a mysterious illness that defies all conventional treatment, he becomes increasingly desperate to find a cure, willing to sacrifice everything for her sake. Their isolated world begins to shift when he encounters a new girl whose presence introduces unexpected complications into their carefully constructed existence. As tensions rise and the boundaries between love, duty, and desire blur, the brother faces impossible choices that will test the very foundations of his beliefs. In his darkest hour, when all hope seems lost, he finds himself drawn toward powers that exist beyond the realm of human understanding—forces that promise salvation at a terrible price. This dark tale explores the depths of forbidden love, the price of desperation, and the dangerous allure of power when faced with unbearable loss. (Source: AniDB)