Bio: This alternate form of the Tenth Doctor was created when Donna Noble touched the regeneration energy-infused hand of the true Tenth Doctor. He is the fusion of the Tenth Doctor and Donna—half human, half Time Lord. He has one heart and no ability to regenerate, but ostensibly the same mental faculties and memories of the proper Tenth Doctor.
He appears to have started a romantic relationship with Rose in the alternate universe described as "Pete's World" by the Tenth Doctor in "Doomsday".
Notes: It's difficult to put a precise name to this Doctor, because none was ever offered on television. The name "The Doctor (10)-Journey's End" seems appropriate enough, as it identifies the televised story in which he originated.