Note: A good amount of these events have been altered from events that occurred at a past game, and from psl threads.
History
Not all endings are happy...
Following the events of Journey's End, the Doctor's clone, sometimes known as 10.5, was abandoned by Rose Tyler at Bad Wolf Bay. As soon as the Doctor had left, Rose slapped him, and the two argued. With a second thought, Rose single-mindedly used the dimension jumper she'd been using all that time, and disappeared from view. Little did he know, Rose ended up in a pocket dimension, one where the Doctor existed, but he wasn't quite the Doctor either of them had known.
Following Rose's disappearance, the Doctor's clone was taken in by Jackie and Pete Tyler, who began to see him as a surrogate son, of sorts. He took on the name John Noble, in honor of the Doctor's often-used alias, and Donna Noble herself. He began to split his time between working at Torchwood, filling Rose's old position, and helping to care for Rose's little brother, Tony. Three months passed in parallel earth time, before he finally decided to search for Rose. He was determined to bring her home, even if she didn't want to be with him, but hoping she would change her mind anyway. He fashioned a device, much like hers, that would allow him to move between worlds, if only briefly, without disturbing the void and unleashing chaos again. After what seemed to be three long weeks of searching, he found her, in the pocket dimension, living, rather unhappily, at that, with the altered version of the Doctor.
What Could Have Been
This altered version of the Doctor was somewhat cold, and a bit neglectful of Rose, which was something John saw automatically. John came to the believe that this was Doctor who had lived through similar events, and had changed for the worse because of it.
John and Rose reunited on somewhat friendly terms, and she ended up apologizing for what she'd done to him on the beach. It renewed his faith, and gave him hope that things would work out after all. His faith grew when she finally gathered the courage to leave the alternate Doctor, and move in with a friend. This friend could see just how much John truly loved Rose, and attempted to help him win her over. She convinced him that he needed to be his own man, separate from the Doctor, and even tried to help him out by advising him to change his clothing style, and even bought him clothes. This ended up really helping him, and he soon came to realize that he might have had the Doctor's memories, and some of his emotions, but he was not the Doctor, and didn't want to be. A new personality, with some combined parts of the Doctor and Donna, began to form. Before long, John and Rose were actually moving towards becoming friends. Then a single weekend seemed to change everything.
The pocket dimension was strange, and had a way of effecting its residents, mind and body. For a single weekend, John and Rose seemed to be cursed, and found themselves living the life that could have been, if she'd only stayed with him. They shared a dream on that Saturday, and the following day, for an entire twenty-four hours, they believed themselves to be happy, in love, and expecting their first child. They made love for the first time, unaware it was for the first time at the moment, and John ended up proposing. The Monday afterward, they wake up in each other's arms in bed, both panicking a bit at the unexpected situation. Rose blamed John at first, but soon, she apologized. John was hurt, confused how his brilliant mind could have been susceptible to such a trick. The two ended up sharing two rather passionate kisses before she fled the house in which he was staying.
Hate That I Love You
Shortly after that fateful weekend, John ended up meeting and adopting a puppy, a Chihuahua he found making a late night snack of his favorite cookies. He named her Bella Donna, in honor of the woman he now regarded as a sister, to some effect.
And he and Rose's friendship seemed to grow after that, despite what had happened, and the fact that Rose couldn't quite remember it. She was sweet, and helpful, and supportive. It was more than John had even dreamed of.
Then, things happened to change their relationship again.
Something fairly sexual happened between them, not the actual act, but something rather close. After it happened, Rose went into denial, and was angry with him about it. This angered John to the point that he showed up, clad in a pair of leather pants her friend had given him, and the two ended up in quite the heated up in quite the heated argument in front of her friend. Their anger quickly turned to passion, however, and before her friend could even make it out the door, they were already seconds away from having sex.
That night only seemed to be the beginning of love-hate/friends-with-benefits type relationship. They'd fuss and fight, normally over his feelings for her, and the other Doctor, and then the anger would boil over into passion. And once it was all over with, they'd forgiven each other. John knew it wasn't a healthy relationship, far from it, but he couldn't seem to control himself, and neither could Rose.
Another Chance
Eventually, after weeks of going around and around, Rose finally seemed to soften up a bit, and offered John a real chance at a relationship. They began to see each other, on a semi-regular basis, and John felt himself happier than he ever had been. She often asked what he'd do if she decided to go back home, and he swore he'd follow.
Three months after he'd first showed up in the pocket universe, Rose put his loyalty to the test.
She up and left one morning, before he'd even woken up, and had gone home, to the parallel universe they'd originally been left in by the Doctor. She left only a note, one in which she finally admitted just how much she loved him.
And John passed that test, giving up nearly everything to follow her. All he could carry was a suitcase and Bella Donna, but he made the trip back to the parallel world, and once he returned, they both vowed never to leave it again.
John's abilities
John has the mind of a Time Lord, as well as the same kind of knowledge and wisdom. He could easily be employed as a scientist or a real doctor of some sort if he wished, without any proper training. He's brilliant, and he knows it. He also has a slight bit of telepathy, able to read minds if he focuses hard enough. He will not do this without permission, however, such is the case with the original Doctor. He can sense other Time Lords, and, in some cases and situations, he might have a bit of a psychic link with the original Doctor.
He has also rather recently gained a very strange ability: He, at times, can have a telepathic link with a human. In most cases, it's very mild, for example, he can sense if Jackie is upset about something, but won't know what she's upset about. That comes without word, and sometimes not even being in the same room. The most extreme case is with Rose, it seems. He sometimes when she's sick or hurt, when she's happy or content, and at times, can connect with her telepathically. All he has to do is reach out, with his mind, and she can hear his voice in her head, and see some of his thoughts. He can also see hers at that time, and they have, on occasion, had full conversations, just in their heads. It's unexplained how he can have this deep of a connection with her, but her has assumptions about it, assumptions that he's still trying to work out.
Unlike the Doctor, John does not have two hearts, and cannot regenerate. He has, however, learned that he's not quite that susceptible to physical pain. He's tough, and can endure better than one might think. He can feel it, but has yet to feel anything truly severe. He can feel pain telepathically, for sure, and experienced it first hand with Rose when her mind was briefly under attack in the pocket dimension.
John's Personality
has all of the Doctor's memories (up until the time he nearly regenerated), and some, but not all, of his personality traits. He also picked up a handful of traits from Donna, and often displays a bit of her attitude and temper, and sometimes acts like quite the smartass. He can be a loud mouth, and isn't afraid to tell someone when to shut up, and does it often. He tells it like it is, even if someone else doesn't like it. He's also seemed to gain a bit of a dirty mouth, particularly when he's angry.
Being human, John is more emotional, it seems, than the original Doctor allows himself to be. John is rather helplessly in love with Rose, and unlike the Doctor, more easily admits it, and attempts to act on it. He may only have one heart, and can sometimes act quite grumpy and a bit rude, but it's a heart filled with love, and he's very caring and compassionate, and a good man.
In spite of that core of goodness, everyone does have a dark side, and John is no exception. He will kill, if it comes down to it, and feels it's necessary. Unlike the Doctor, he will do it without a second thought, as he did when he committed genocide and exterminated all the Daleks. If he felt someone he loved was in danger, i.e. Rose, he probably would have the strength to actually kill someone. As time has went on in the parallel world, he tried to control this darkness, and get past it, though he knew it might always be there, deep down. While in the pocket dimension, he discovered a rather strange way to handle his dark inner anger: passion. His fights with Rose were often filled with cursing, yelling, and looks that could kill, but what came afterward was something different altogether. Rough, almost violent desire would take him over, and then he would take Rose, in any way he pleased. He never forced himself on her, however, and always felt the need to tell her to admit she wanted it. He continues to have this trait, of turning anger into passion, but is a bit more gentle about it now.