Doctor Who: Every Doctor's Darkest Moment
8. The Eighth Doctor - Becoming The War Doctor
As the Time War raged across the cosmos, the Eighth Doctor was given a choice. Mortally wounded after crashing to the surface of the planet Karn, the Sisterhood offered him a choice of who he would become next.
The Eighth Doctor could have regenerated into another incarnation. This ninth incarnation could have remained as the hopeful hero that muddled on through, helping out on the fringes of the conflict between the Daleks and the Time Lords.
But instead, the Eighth Doctor actively chose to turn his back on the name of the Doctor, and embrace the Warrior persona.
The Night of the Doctor was one of the real highlights of Doctor Who's 50th anniversary. By showing us how the Time War had broken the most youthful, energetic, and romantic of the first eight Doctors, Steven Moffat demonstrated how hopeless a conflict it truly was.