This new Doctor might be darker and more unpredictable, but he certainly hasn't lost his sense of loyalty. As a Time Lord, he has always carried a certain sense of responsibility for those in his charge as well as for anyone else he might encounter on his journeys. It's quite different that whatever else has changed, the Twelfth Doctor still carries this sense of loyalty and responsibility as seen by the way he promised the dinosaur in Deep Breath that he would do whatever it took to keep her safe until he could take her back to her own time. As we also saw, his loyalty to his friends was him chief motivation in going after Half-Face Man; if he hadn't, the clockwork droids would have killed his companions, and he never would have forgiven himself. Mind you, his loyalty isn't limitless. For those he doesn't like (soldiers, for example), he can be quite dismissive and not really care one way or the other about the fate they encounter. But for those for whom he cares, for the innocent, for the helpless, there is nothing in the universe that would stop him from saving them. His dark side might be off-putting, but beneath the harsh exterior is a pair of hearts that cares more than the Doctor might openly admit.
Paula Luther hails from Pennsylvania and has been an avid Whovian since 2008. She enjoys writing (obviously), reading, dancing, video editing, and building websites. She has also self-published two books on Amazon, "Bart the Bard" and "Android Mae and Other Stories".
