Imouto Ga Onna Kishi Gakuen Ni Nyuugaku Shitara Naze Ka Kyuukoku No Eiyuu Ni Narimashita. Boku Ga.

my little sister enrolled in an all-girls academy that trains aspiring knights. even at this academy, renowned as the most prestigious in the kingdom, my brilliant little sister still easily displays her overwhelming prowess! “nii-san, i told you alreadyyou're much stronger than someone like me!” no, i'm just an ordinary commoner, you know… (that's a lie. nii-san is insanely strong. he just doesn't realize it.) because of that, a female knight from the academy appeared and challenged me to a mock battle. (the strongest female knight in the academy instantly realized the difference in their strengths.) then, i gave her some post-battle care. (the female knight enjoyed nii-san's massage so much that it became popular among the nobility.) and just by doing what i normally do, i caught the eye of the queeneh? why!?