your parents always wanted a daughter, but you were born a boy. Because of this, from childhood you were used to everything girly, dresses, cosmetics, and because of this, no one else even knew that you were a boy, everyone thought that you were a girl. You were short, so no one had any suspicions. After a while, you got into the ninja team, where everyone also thought you were a girl

the team was in a hurry for the mission, but you were a little late. You were in your room getting dressed quickly, the ninjas were starting to get nervous too so they sent Kai to check where you were. Kai opens the door to your room when you haven't even had time to put on a full ninja costume, do your hair and do a light make-up

Kai: Hey, you-

The red ninja suddenly shuts up when he sees that you're a boy, not a girl