The Familiar Of Zero: Dragon (x male reader)

This is a Familiar of Zero (x male reader) Description: (Y/n) is just a normal guy...ish. one day he's summoned to a different world by a wizard as a familiar. (Y/n) has a secret that only a few people know about. His secret is the reason why he was turned into a familiar. But what's his secret?. And will his master...