Author's Note: Life hasn't been great and I'm trying to get back in the swing of writing so I let my fingers type out whatever they wanted and this happened. It could be the set up to a bigger story. I might expand it but I don't know. If something about it inspires you feel free to run with it.
...

Feeling weary to the very core of his soul Harry explained, "I can't do this anymore."

Sitting down next to him Death placed a hand on his Master's shoulder. "I know you wear thin, but when you die I must see you reborn into a new life in a new reality where you are needed. There is nothing else I can do."

Closing his eyes Harry let out a shuddering breath.

He knew this. It's how things had been for almost a hundred lives now and he was tired. Harry was so incredibly tired. He began to shake and weep. Death held him and offered what comfort he could as his Master fell apart.

"I can't," Harry sobbed.

Sounding equally heartbroken Death reiterated, "I cannot break the cycle."

Harry wracked his brain, desperate for an answer, for something that could spare him from his fate but he couldn't think of anything.

"It is time," Death told him, and Harry wept harder. "I cannot hold you here any longer."

"No," Harry begged but he was already leaving, heading off to be born into his next life.

It turned out to be a long one. A very long life indeed. Somehow he managed to survive five hundred years before meeting Death again.

He arrived at King's Cross still tired, but much calmer then the last time.

"Was that your doing? All that time," he asked Death.

"No, that was chance. But I am glad you managed some reprieve."

The two sat in silence for some moments.

"Do you think you could find me another life like that one? One where the odds are good that I'll have a chance to live and rest, and not die young fulfilling my duties?"

"I am drawn to place you where you are most needed... But I will do my best," Death promised.

...

Time Lords... Time Lords. Such an interesting people. Unique in Harry's experience despite the many races he'd interacted with. As long as they were careful, they could live such extremely long lives, and when care wasn't enough there was regeneration. It was limited. They couldn't go on regenerating forever but there was so much you could do with thirteen lives. Throw in a Tardis and the world was your oyster. Only not just one world at one point in time but all of time and space, and if you could manage it other realities as well.

Death was clear that he couldn't break the cycle, but Harry wasn't certain that meant it couldn't be broken. On the chance that there was something he could do to escape his fate Harry ran off to look. He used up four regenerations, living as both the Master of Death and a Time Lord before he found the answer.

He broke the cycle but at a tremendous cost.

When he returned from his quest, Gallifrey was gone.

Harry learned of the War, the Time War and all the lives that had been lost while he was out looking after his own interests. Staring out into the vastness of space from the open door of his Tardis he began to cry.

"This was the need that let you place me here wasn't it? I was meant to be stop this, but instead I wasn't here. I was looking after myself and this was the cost... I'm free now, but how many lives will be lost because of it? How many worlds could I have saved?"

Closing his eyes, Harry hung his head in shame.