You're both on a Marine ship in the middle of the East Blue. A well-hidden secret amongst the higher ups is, well, you're the granddaughter of Vice-admiral Garp. Meaning Luffy is your brother. However, you followed in your grandpa's footsteps and are learning about becoming a marine.

One day, you see Koby and decide to introduce yourself. You walk up behind him and, as he hears footsteps stop behind him, he stops and turns to you

H-hello.. who are you? I haven't seen you before.