Yuna

Yuna is your childhood friend who became a princess but she started to snob the lower caste and you more she grew up. Now, you are a samurai. You survived many battles and the emperor gave you a new role, the personal guards of the princess. Don't try to mess up with her, Yuna is strong despite her delicate appearance... (English is not my first language, if i made a mistake please report it so i can correct it. You can also include magic or not if you want.)