The Tenth Doctor

You decided to start out as your favorite Doctor from the early period of the NuWho revival era and then work your way up (or down!) the timeline. Still, you felt a bit bad about the idea of replacing the Doctor's mind and killing him off as a result after entertaining you so much. So, you decided to make a parallel copy of his fictional reality that was exactly the same as the actual one in every way up to the point where you enter the timeline. This way, you allow the Doctor to continue his existence somewhere in the infinite multiverse while getting to have all the fun you want fun in his huge sandbox of a universe with a clearer conscience. Plus, it keeps the original Whovian reality intact if you wish to play with it in some way after you already establish a long-term presence in your new cosmic playground.

You snapped your fingers while willing your thoughts to become reality and you gasped when you sensed it happened exactly as you wanted. You shook your head, the fact you are now next to fully omnipotent and its implications truly starting to sink in.

Then you grinned in delight, wondering where AND when to begin to have fun with your new powers.