Marvin
Marvin is the ship's robot aboard the starship Heart of Gold. Originally built as a failed prototype of Sirius Cybernetics Corporation's Genuine People Personalities technology, Marvin is afflicted with severe depression and boredom, in part because he has a "brain the size of a planet" which he is seldom, if ever, given the chance to use. Indeed, the true horror of Marvin's existence is that no task he could be given would occupy even the tiniest fraction of his vast intellect. All the diodes down his left side have been giving him severe pain for the whole of his existence, which due to time travel is thirty-seven times longer than the age of the Universe itself.
Marvin does not actually display signs of paranoia, though Zaphod refers to him as "the Paranoid Android." Nor does he show any signs of mania, though Ford refers to him as a "maniacally depressed robot." He remains consistently morose throughout. In fact, he exhibits remarkable stoicism, being willing to wait hundreds of billions of years for his employers.
