|Aliases||D22, Young Adult Dexter|
|Family||Dee Dee (sister), Mom (mother), Dad (father), Grandpa (grandfather), Fergle O'Reilly (uncle), Dextamina (great great aunt)|
|Occupation||Cubicle worker; slave|
|Interests||Science and games|
|First Appearance||Babysitter Blues|
|Voiced By||Christine Cavanaugh|
Number 12, D22, or Young Adult Dexter is Dexter in the future as a young adult. He is a complete slave to Mandark and works in a cubicle as a low-rez worker. Mandark is very mean and abusive to him and he is always getting harshly and severely punished for doing even a little wrong, such as "almost being late". These punishments are usually carried out through such means as "public flogging", or, in layman's terms, being brutally whipped with what appears to be a whiplike laser. It can be inferred that such events are more than likely what led to the drastic shift in character from Dexter to Number 12. In fact, through such brutality along with Mandark seemingly ruling the world, he seems to have forgotten how he acted as a child, stating, without hesitation, "Oh, I've always been like this."
Number 12 was the first of Dexter's future selves to be visited in Ego Trip, to which Dexter was brought to by a street drone after analyzing his DNA and ordering him to "return to his work station". Shortly after arrival, Dexter bears witness to the flogging of his future self, and the two Dexters soon after meet face-to-face. Number 12 initially doesn't recognize Dexter, however, and even after being informed that he is speaking to his past self, he explains that he must continue his work, most likely for fear of another punishment. Dexter soon uncovers the stowed-away blueprints Number 12 had most likely been working on before Mandark had overthrown the company, along with the Neurotomic Protocore, having been safely hidden away from his nemesis even after all these years. With much persuasion, Dexter makes Number 12 leave his slave-driving job behind, along with his "name", reclaiming both his name of "Dexter"... and his trademark purple gloves. However, due to the commotion in the office, the Protocore is left out in the open, and soon discovered by Mandark. The two Dexters sneak back into Dexter's laboratory-turned-rec-room, and head to the future.
In the special's fourth act, in which Dexter, Number 12, and Old Man Dexter meet Action Dexter, it is revealed that it was Dexter's meddling that resulted in the dystopic future Action Dexter has had to endure, the Protocore having been snatched up by Mandark and set to "negative", numbing the people of the world's minds and allowing Mandark to hoard all technology for himself. Number 12 realizes this, but is quickly hushed by Dexter jabbing an elbow into his arm.
Number 12 not only aids in the building of the robot used to storm Mandark's fortress, but also fights in the final battle to defeat his nemesis once and for all. In a series of events in which Number 12 is tormented by Executive Mandark by being repeatedly slapped around and having his glasses taken from him (which are immediately stomped on and destroyed), he reaches his breaking point and finally lashes out at his old boss, attacking him and stealing his glasses for himself. It is upon Number 12's revelation that the other three Dexters make an attempt to switch the flow of the Neurotomic Protocore from negative back to positive. In the grapple between the Dexters and Mandarks from each time period, Number 12 can be seen both holding Mandark back by his cape... and forcing his former boss back via a boot to the teeth.
Number 12, along with the other Dexters, returns to his time period after saying goodbye... albeit with a smile, and a touch more of self-confidence.
Number 12 looks very similar to Dexter, with the same curly, red hair, pale skin, and glasses, though much taller, lankier, and somewhat scrawny-looking. His head is also somewhat of a different shape, and his labcoat has four buttons on it. He is more often than not seen with a slouch, despite his height. Interestingly enough, he seems to be even more pale than his child counterpart in some scenes of the special. It is unknown whether this is the result of a simple coloring error, or if perhaps being shut inside the corporation for so long has indeed deprived him of needed light.
Number 12 is shown to be much more mild-mannered and timid than Dexter or any of his other counterparts, more than likely due to Mandark's abuse over the years. He seems to not believe he is a genius anymore, at least in his introduction, and generally lacks the aloof attitude of child Dexter. However, by the ending of the special, he seems to be a bit more well-adjusted after standing up to Executive Mandark, having even taken a big part in the fight against all the Mandarks, and it is likely that this confidence-boosting event would result in his rebirth as Action Dexter.
- "8:52? Holy cow, I'm almost late! I'd better log on!" -Ego Trip
- "Y-y-yes, sir...?" -Ego Trip
- "Can I have some padding?" -Ego Trip
- "No, no! Please, don't hurt me!" -Ego Trip
- "I'll have you know that what I do here is very important! I design these cubicles." -Ego Trip
- "...Dexter?" -Ego Trip
- "I forgot how much I hate time travel..." -Ego Trip
- "I'm typing, I'm typing!" -Ego Trip
- "Looks like a bomb hit..." -Ego Trip
- "Goodbye, Dexter!" -Ego Trip
- In the credits, he is referred to as "D22", possibly indicating that Number 12 is Dexter at 22 years of age.
- In the episode "Babysitter Blues", he had pimples, drool, and a pocket protector filled with pens, but in "Ego Trip", he didn't have any of that. This could be due to being older then he was in Babysitter Blues, as he was merely a teenager there while in Ego Trip he is a young adult.
- Although Dexter has an accent, Number 12 doesn't.
- Time travel apparently makes him nauseous, though this does not seem to be the case with the other Dexters.
- He seems to have a tendency to fall on his face, illustrated a number of times within the special.
- His labcoat appears to be slightly too big on him, covering part of his upper legs and having sleeves that go up to his palms.
- Despite his height, he is rarely seen standing or walking without a slouch. This can most likely be attributed to many years of being hunched over a computer, typing.
- His voice is actually in a higher pitch than that of his child counterpart.