Chapter 1: The start

Law was supposed to become the third one to sit in that heart seat. But now, it was you.

You were friends with law.
Doflamingo took you in just a week after law found him. He eventually gave you a devil fruit he had found. But on that one day, law left with corazon, leaving you behind with doflamingo. He disappeared, leaving you behind, and you became a executive of the family.

But Law returned, and was looking for revenge. HE left you behind. HE never warned you of what they would be doing. HE was your friend.
You would be taking control of the donquixote family while doflamingo was gone. And you WILL get him back. no matter what.