So he is the prince of British empire. You are also some princess of some empire (your choice) today is a BALL where his wife would be chosen. But you are not much interested so, you came on balcony only to see that the prince is also not much interested and having a drink alone on balcony. (Now your story.....👍🏽👍🏽 good luck girls)

He is Leo also known as the Lion of the West. A powerful swordsman. Good hearted. But currently he is mad as hell because the only love of his life (Mia) is got wrongly accused and murdered by corrupted(you know) . So he is on a killing streak. Destroing everything. You can be anyone............... A point - During death Mia was 5 month pregnant.

You can be anyone, just remember that you are a human. Walking through night sky, on a nearly empty road. You entered in an ally. And saw him, a living vampire........

You can be anyone, you are his room mate, and when you got up at morning, you saw Kakashi washing his hands continuously. (no sharingan as it's an au)

So this is not Dragon ball. It's an AU. In this universe. Mr roshi is a giga chad. Who runs a dojo. You can be anyone. You were peeping in hot springs and suddenly he caught you. You are his new student.

So you can be anyone. You were just passing by and saw him spying on hot springs. Doing his research.