Legion

"My name is Legion, for we are many."

Origin
A Gestalt entity created by some of the greatest minds in the 23rd Century, for example Heideger, Davro, Quayle and Holder. They were experimenting in collective intelligence when Legion was created as the product of that research. When composed of those great minds, Legion was one of the most intelligent sentient beings in the universe (supposedly). The facility when seen in the episode is littered with pieces of art, which according to Kryten's connoisseur chip, fulfilled all 10 requirements for being masterpieces. Also, he was quite the engineer, indicated by the hard light drive that gave Rimmer a physical form and a star drive that he gave to the Dwarfers, although whether the malfunction that occurred when they set it off was caused by Legion himself or just by a mistake made by the Dwarfers is unknown (most likely the latter as it worked, but due to a bad connection to the existing engines, it didn't take them with it. However, of course after a while, nature took its course and Legion confirmed that the scientists never left; they just died of old age.

Encounters with the Dwarfers
When the Dwarfers showed up in the Legion episode, he seemed to be attached to life and did not want to return to, as he put it, "A limbo state of non existence", attempting to make the group happy to encourage them to stay. After discovering the truth about his nature, the Cat initially assumed that Legion couldn't hurt them without hurting himself, but unfortunately the combined magnification of the crew's neuroses meant that he was capable of insanely irrational behaviour. Fortunately, Kryten managed to eliminate the threat posed by Legion by knocking out Lister and Cat and turning Rimmer off, leaving Legion only able to duplicate Kryten's personality; with Kryten the only source for his psyche, he was now incapable of malice, and was automatically conditioned to help the human crew members over his own self. As he helped Kryten move Cat and Lister back to Starbug, Legion commented that, having experienced their combined minds, returning to his state of non-existence would be almost like promotion.

Before Starbug
Millenia before Starbug appeared

Nicknames
It is unknown whether Legion was his original name that the scientists gave him. He is only known as Legion due to the metaphor "My name is Legion, for we are many", in direct reference to his status as a gestalt entity.

Personality
Legion is intelligent and well-spoken. He has great intelligence, and usually acts patiently with Dwarfers. However, when they attempt to leave, he turns violent, using their connection to him to inflict pain on them.

Skills
Depends on his components. While made up of the greatest geniuses of the 23rd century he was evidently a scientist skilled in many fields as well as a master artisan. While composed of the Red Dwarf crew he probably possessed knowledge such as Cat's of gaudy fashion combinations, Lister's of Indian food, and Kryten's of sanitation techniques. In his later incarnation, Legion possessed a genius-level intellect due to having the combined intelligence of the four Dwarfers. In his original incarnation, in which he was formed from the combined intelligence of multiple celebrated scientists who were already geniuses in their own right, his intelligence was so vastly beyond the genius-level that it is difficult to fathom. He remembers what he did in previous incarnations, but if his combined intelligence is insufficient to comprehend what he did, he won't remember how he made it or why.

Quotes

 * Legion: My name is Legion, for we are many.
 * Legion: I just want you to be happy!
 * Legion: (After stabbing his own hand and thereby stabbing all the Dwarfers hands) The next hint of insurrection, and the scalpel ends up here! (Indicating his groin) 
 * Kryten: That kind of tough talk doesn't scare us!
 * Cat/Rimmer/Lister: YES IT DOES!