Twelfth Doctor
The Twelfth Doctor is the twelfth incarnation of the Doctor.
After the Eleventh Doctor regenerates for what-ever reason, this Doctor is born. He has red hair or 'ginger' as the Tenth Doctor had always wanted and wears a fur coat like the Second Doctor.
His companions are Anna and Guinevere Winchester. He has appeared in the short stories, Good Companions,Greenaway. Half way through this regeneration, he travels to Arthur's World and helps Arthur fight against Morgaine and Mordred, becoming the legendary 'Merlin'.
After returning he was stranded for 1000 years on Mount Kukoeuk on Ant'ykhon, becoming known as Muldwych, later assisting Bernice Summerfield and Ace with the The Doctor's TARDIS (NA: Birthright).
After this ordeal he gave the Doctor time rings for Bernice and Jason Kane's wedding.
At some point in the future after this he regenerated into the Doctor's thirteenth and final incarnation, the Valeyard, which unlike previous incarnations was pure evil, an expression of the Doctor's dark side.