Max Capricorn

Max Capricorn was a businessman from Sto who owned Max Capricorn Cruiseliners, which operated the space cruise liner Titanic. In the latter years of his life he had become a cyborg with only his head remaining organic; since his people were prejudiced against cyborgs Capricorn had to hide his true nature and communicate with others through a hologram.

After spending 176 years running his business, Capricorn's company failed and his board voted to kick him out. To get revenge, he sabotaged the Titanic's voyage by bribing Captain Hardaker to cause asteroids to strike the ship, and programming the Heavenly Host to kill any survivors. He intended for the Titanic to crash into Earth, detonating its nuclear storm drive and destroying all life on the planet. His company would then be wiped out, its board members jailed for mass murder, while Capricorn lived out his retirement on Penhaxico Two.

Capricorn's plan was foiled by the Tenth Doctor and a band of Titanic survivors. The Doctor found Capricorn on deck 31 with an indestructible omnistate impact chamber, within which Capricorn had planned to ride out the crash. Capricorn cancelled the Titanic's engines himself, sending the ship plummeting towards Earth, but Astrid Peth used a forklift to lift his cybernetic casing and throw him into the storm drive. (TV: Voyage of the Damned)

Parallel world
In a parallel world in which the Doctor had died a year prior, Capricorn's plan succeeded. Despite not wiping out all life on Earth, the Titanic destroyed London and irradiated southern England, turning Britain into a third world country and beginning its transformation into a police state. (TV: Turn Left)

Other information
Capricorn's trademark was a gold tooth that flashed — both on camera and in person — when he introduced himself. (TV: Voyage of the Damned)

Behind the scenes

 * Originally it was intended that Max Capricorn should have two milky-white eyes, but George Costigan could not see with both "cataract-lenses". Therefore, one was taken out, and the character was rendered with only one "bad" eye. (PCOM: Voyage of the Damned) This original intention is also noted in his character description on page 63 of the online shooting script release made in promotion of The Writer's Tale.
 * Iconic American actor was offered the role of Max (after being considered for the part of Mr Copper), and expressed interest, but the idea fell through, and Costigan was signed. (REF: The Writer's Tale)

The Visual Dictionary
The non-narrative source Doctor Who: The Visual Dictionary gave further information about Max Capricorn: His protective casing held an oxygen field, a device that allowed him to control the Titanic's engines, and a life-support system, which was secretly built on Sto.