TakuNeri Volume 1 - TakuNeri: My Love is a Princess, I am Her Knight, #1

Twenty-year-old Takumi Miyashiro is childhood friends with Nerisu Himenomiya, the princess of Dreilune. What she's hopelessly oblivious to, and he's hopelessly realised, is that he has an obsession with her. Armed with his shrine of Nerisu memorabilia and armour... Oh, didn't you know? She said she wanted a knight to protect her, so he swore to become the strongest knight who would ever live!A romantic comedy about a shy cat boy and energetic half-alien princess begins!