This is rather lovely! I love your portrayal of John Smith, how he handled his new/not new self and the memories of the man he had never really been, the two hearts he had never had, all the insight. The companions part was wonderful, I'm in love with the idea of him working with the Brigadier, and it's great that you showed some companions had wonderful endings and some tragic ones—very realistic. Donna and Liz especially made me swoon. And Sarah Jane of course! Priceless. And then the Master part was both the point and the climax of the piece, and I really like the way you handled him, the description, John's overexcited babble and his annoyance in response, and finally their getting to be opposed again, and how that brought John what he'd been missing, finally. Pretty nice :) Thank you for this!

A few typos:

"And there are other things, small or significant that makes him having to adjust and think through constantly, but that is fine, really.": that make him have to adjust

"Martha and her whole family is gone, they disappeared when the cybermen descend upon London.": are gone/descended

"“What name should I sign it to? Sarah asked and he stammered.": missing quotation mark

"as even Time Lords do eventually, if the don’t change.": they

"perhaps it is just an ordinary human who happen to look like his best enemy.": happens

:)