Harry was bored with Life. It was as simple as that, he had lived for years and had seen his children, grandchildren even great-grandchildren pass on. There was nothing left for him in this life. However, the main causes of his current problem were the wand in his hand, the cloak on his shoulders and the ring on his finger. A couple weeks after the Battle of Hogwarts, he heard a voice in his ear that no one else could hear.
"You who has united the three Deathly Hallows and embraced death without fear, you shall be declared the Master of Death. Long may you live."
The statement, 'Long may you live' as a lot more literal than he first realised, it had rendered him immune to death by any natural means and even stopped his ageing and due to his skill as a fighter he was able to protect himself from the many assassins sent by dark wizards looking for revenge.
However, he knew of one thing that might work, there was a fourth object that death had been involved with the creation of, the Veil of Death. If anything to could allow him to move on it would be this, and it would also mean that the curse of the Death Hallows would end as well, ensuring peace after his death. Though, once he steps through, he is brought back to the Kings Cross Station. Looking around, expecting to see Dumbledore here after the last time but instead, he hears that voice the one that started all his problems.
"We meet at last. Greetings, Master, I am the being that you know as Death."
He turned around and saw a skeletal figure in a black robe, looking exactly as he imagined a Grim Reaper to look. Confused why he was still unable to move on and angry that he couldn't finally join his parents he questioned the figure in front of him.
"You say that I am your Master, then explain why I am here and what you wanted from me that required that I don't die."
Death let out a chuckle, then starts walking away, gesturing for Harry to follow.
"The reason that you are here and the reason that you lived for so long is simple, you have a greater purpose in life. This purpose of yours required that you enter the portal to the Dimensional Gap that you refer to as the Veil of Death. It requires that be reborn in a new world and become one of their saviours."
Upon hearing this Harry was furious, his life was being controlled again, he already had the prophecy ruin his childhood, he wasn't going to let it happen again. Though, seeing Harry's anger, Death silenced Harry's protests by explaining what he meant.
"You are not being controlled by me, you are my master, I could never do anything that would hurt you. You can turn my offer down, you are not being forced to accept it, I am only offering it to you as if it wants to survive then they will need all the help they can get, they need your help."
Harry thinks for a moment, but he knows that he doesn't really have a choice.
"When you put it that way, I can't really say no can I. Hermione was right when she said that I have a 'saving people thing' and if these people need me to save them, I will do it. So, you said I will be reborn in this new world. I'm guessing that I get to keep my magic and my memories, am I right?"
Death creates a magical circle under Harry then starts to explain what will happen.
"For the first 17 years of your life, you will lack your memories and magic. This is because you will be raised in a church orphanage and I don't want you drawing attention to yourself to early, but on your seventeenth birthday you will regain all of these, it will be more like waking up and being able to remember your dream. When this happens, I will leave you a note telling you what to do next."
The magical circle activates, and Harry disappears, Death looks at the spot where he had previously been.
"Now Master goodbye and I may see you again in the future. Elohim, my old friend, I hope your plan works because if not then my Master may be in lots of danger."