Shinobi no Ittoki

Ittoki Sakuraba is unaware of the danger surrounding him due to his status as the 19th heir to the Iga ninja clan. His mother and uncle have been taking precautions to keep him safe, while his childhood friend Kousetsu has been tasked with monitoring his movements. This close watch makes sense when Ittoki is asked out by Satomi Tsubaki, but her true intentions are revealed when Ittoki visits her home. Tsubaki and her accomplices aim to assassinate Ittoki, and he is rescued by his uncle and Kousetsu, who are revealed to be ninjas.