とらいあんぐるハート ~Sweet Songs Forever~

"Triangle Heart ~Sweet Songs Forever~" is the third installment in the "Triangle Heart" series, initially an adult game released by JANIS Computer Software in 2000. The series is characterized by its "triangle" relationships involving one boy and two girls, although many other heroines exist in the games. It was later adapted into an OVA animation by Mook and Seven Arcs, and is best known for its spin-off series, "Magical Girl Lyrical Nanoha". "Sweet Songs Forever" focuses on Kyoya Takamachi, who, with his adopted sister Miyuki Takamachi, vows to protect their childhood friend Fiasse Crystela from a mysterious terrorist organization. Fiasse is a world-renowned singer and headmistress of a special singing school. She inherited an estate from her late mother, making her a target of conspiracies. To protect her, Kyoya and Miyuki become professional bodyguards like their father. The plot also introduces Ellis McGaren, Fiasse's bodyguard, who has a complex relationship with Kyoya and Miyuki, driven by both jealousy and her past. This story combines themes of combat, friendship, and protection, serving as one of the origins for the "Magical Girl Lyrical Nanoha" series, although they are not part of the same continuity.