Able was a "production brother" to Kryten, sharing the same 2X4C motherboard. Wheras Kryten's covering plastic was black, Able's facade was green. Unlike his dutiful, guilt-ridden, servant-to-humans brother Kryten, Able was a drug-addicted wastrel and servant to Simulants and Kinitawowi.
Able appeared in one episode of Series VII, at the end of which he sacrificed his life to save the Dwarfers, destroying his master the Simulant Trader and the Kinitawowi slavemaster aboard the SS Centauri.
Much of Able's early life is left as a mystery, however there are hints that although he was similar in construction to Kryten, Able originally had vastly superior software. Whereas "bog-bot from Hell" Kryten's software was for sanitation, having being installed at "Toilet University", Able's software was diagnostic.
Able's original crew all died when the Space Corps spaceship he was on crashed, leaving him alone - as what had happened with Kryten on first the SS Augustus and then the Nova 5. Whereas Kryten was rescued by the Boys from the Dwarf, Able was eventually picked up by the SS Centauri, which had been commandeered by a Simulant Trader and a Kinitawowi associate.
The Simulant Trader broke Able's will by telling him the password to locked-away files in his head, that revealed the truth - the entire 4000 series was an in-joke by its creator Professor Mamet, and a spiteful mimicry of her former lover, the "buffoon" John Warburton, and the Nega-Drive was an extension to this.
This knowledge caused Able to taking a mechanoid narcotic, Outrozone, and he fast became a "zoney"' a robot who is addicted, dependent, and whose motherboard has been degraded by the drug. The drug degraded Able's motherboard to the point where it would take him hours to pull up a piece of memory from his archives, and having a normal conversation was impossible with him.
Encounter with the Dwarfers
When Kryten blew up all his spare heads due to being overloaded by his Nega-Drive, Starbug set a course for the derelict of the SS Centauri to look for more spare Series 4000 heads. However, they encountered the Simulant Trader there, but were luckily disguised as Kinitawowi. Whilst the Simulant kept them talking, his accomplice, a real Kinitawowi, ransacked Starbug and stole Kryten.
When Kryten awakens, he is amazed to see another Series 4000, and one who shares the same 2X4C motherboard as him, meaning that they are technically brothers. Kryten however is perturbed to discover that he is "zoney" addicted to Outrozone and then says that is no brother of his.
The Centauri was too fast for Starbug, so the Dwarfers pretended to have placed a bomb aboard it. It comes about and the Simulant, the Kinitawowi, and Able beam aboard Starbug. The Simulant tells Kryten the password to access a secret file in his CPU, which is the same as his serial number, 2X4C. Kryten is broken by knowing the same truth as Able. Hearing the password causes Able to have a moment of clarity, and he throws his head at the Simulant knocking it out. Lister incapacitates the Kinitawowi with a kick and a blast from a Bazookoid, before beaming them back to the Centauri and escaping.
Starbug hides in an asteroid belt, hoping to escape from the Simulant via silent running. However, Able, in a drug-induced daze, falls on the steering wheel carelessly giving away their position and the Centauri begins attacking Starbug with laser cannons. When it becomes obvious that Starbug has no chance of surviving this battle, Able takes an escape pod, causing Kryten to curse Able and say that he is a traitor and no brother of his.
Able attacks the SS Centauri with the pent up emotions stored in Kryten's and his own Nega-Drive, causing the Simulant Trader to first suffer a fit of depression, then go berserk and start firing his bazookoid at the ship's controls, eventually causing the SS Centauri to explode. The massive blast also forces the pod to do a dive into one of the asteroids, killing Able. Kryten retrieves Able's off-line body from the crashed pod, carrying it aboard Starbug to perform last rites and finally calling him his brother.
- Simulant Trader: [presenting a damaged Kryten] "Got a little job for you Able. Looks like a Nega-Drive blowback."
Able: "Oh wow, another mech!"
Simulant Trader: "Fix him ready for market or I'll apply the electro-leads to your nipple nuts."
Able: "Fix him, or get fried nipple nuts. Erm... Er... I think I'm gonna choose the fix him option! Deal!" [holds out his hand to shake it]
Simulant Trader: "And hurry up, you stupid zoney!" [hits Able over the head with a lead pipe]
Able: "Is now a good time to ask about a pay rise?" [Sim hits him over the head again] "Ahh, I'm almost out of Outrozone, I need some more."
- Able: [Grunting and injecting some Outrozone] "Totally tubular!"
- Able: "You're my bro! Hey, wow, you wanna try some Outrozone?"
Kryten: "Outrozone's dangerous and highly addictive!"
Able: "I just use it now and then. It helps me through the day."
- Able: "Uh, ok. The ship I was on, er... it kind of crashed a bit. They crew just lay there and didn't talk to me anymore. Then after a couple of years i figured they must be dead. A long time later, the Simulant guy came picked me up. He's a bit of a psychopathic killing machine, but he has his good side."
- Kryten: "I'm not your bro, and I do not touch Outrozone! It corrupts your circuit boards!"
Able: [Gurning] "Well, that's what people say, but where's the evidence? [chuckles to himself] "Have I just said that?"
- Able: "The truth is in there. That's what turned me into a zoney!"
- Able: "Heads!" [Able trows his head at the Simulant Trader, knocking it out]
- Able: "Think I may have pressed a wrong button."
Kryten: "You have jeopardised the lives of the entire crew, breaking the most basic fundamental command codes!"
Able: "I'm sorry. I didn't mean nothin'."
- Lister: "He gave his life for us, and we hardly knew him."
- Kryten: [carrying Able's body] "He ain't heavy, Sir. He's my brother."
Behind the scenes
- The quote "he ain't heavy, he's my brother", is a possible reference to Judge Dredd, as the lawman said this as he carries his recently-killed brother Rico out of his apartment in "the return of Rico" set in 2099. It is also a reference to the song of the same name by the Hollies.
- Able is likely named after the Biblical character Abel. However unlike Abel, who was murdered by his brother Cain, Able sacrificed himself for Kryten.
- Able was not originally intended to be a brain-rotted "zoney", but in early drafts was intended to be brilliant and far superior to Kryten. Able was going to show what Kryten would have been like if Lister hadn't been there to help him break his programming, lie and develop human emotions, since despite his brilliance Able was servile and without free will. This idea was later altered so that Able would have free-will, but the character would be an exploration of drug addiction in the Red Dwarf universe and ultimately have redeemable and even heroic qualities. Series VII article on Red Dwarf.co.uk