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I am the fourteenth Noah who destroys everything. I am Nea.
—Nea introduces himself to Allen Walker.
Nea D. Campbell (ネア・D・キャンベル , Nea D Kyanberu), also referred to as "The Fourteenth", "The Pianist" and "The Musician", was a traitor and disowned member of the Noah Family. He is the younger twin brother of Mana Walker and the adopted uncle, as well as the host of Allen Walker. He was the only individual, besides the 9th of the Noah Family Road Kamelot and the Millennium Earl, who is able to control Noah's Ark by playing his piano.
Initially, Nea simply appeared to Allen as a shadowed figure with no distinct facial features wearing a large overcoat. Once, he appeared briefly to the Earl in his mind as a young man with unruly, darkly-colored hair.
In his Noah form, Nea appears as a young man of average height with short, unruly somewhat spikey very dark hair with a line of stigmata on his forehead, wearing a dress shirt, vest,a simple cravat, and an overcoat and white gloves. His facial features have been noted by both Wisely and Allen as making him strikingly similar in appearance to Tyki Mikk, though Tyki has more mature facial features and Nea's hair is shorter and he lacks Tyki's facial mole. Considering that in Allen's body he as splitted pupils like the earl it can be assumed that his full-noah form also have slitted amber eyes.
In His Human form, his skin is rather fair and his hair seem dark brown. He has darkly shining eyes . As a child, Nea weared cozy clothings with straps and a ribbon 
Not much is known about Nea's personality. He often speaks gently to Allen in their encounters, and seems to mean him no harm, despite the fact that he will consume Allen's body and be reborn. It is also apparent that Nea's will is to gain revenge against the Millennium Earl upon his rebirth. No motive has been given as to why Nea betrayed the Earl, though Cross Marian implies in his conversation with Allen Walker that Nea discovered a third side to the war between the Noah Family and the Black Order. He stated that he wanted to become the millennium earl. However, Nea has shown a ruthless disposition, going as far as to bash Johnny Gill's head into a wall just to converse privately with Timcanpy.
He was, however, very close to his brother, Mana. Road claims that Nea fought on behalf of his brother. Wisely states that Nea experienced the terror of knowing that there is nowhere a Noah can flee and hide from the other Noah 35 years ago.
Nea seems rather self confident as he provokes the Millennium Earl several times even in the presence of other Noah Family members.He goes as far as revealing a shocking truth to a mentally unstable earl as he is alone and not even used to his new body. He also took delight in pushing the Earl in such a state, showing a rather sadistic particular devious disposition. He is also a manipulative, easily capable of impersonating Allen in front of his friends.
Nea releases a strong desire to murder according to Howard Link. He hates humans and prefers to act by his own without the help of others and allied with Cross out of necessity. He deeply cares for his Golem Timcampy as shown when he panicked when informed about his fate.  Nea is shown to have a degree of kindness, as despite claiming to hate humans, he warned the Finders, who were sent to capture Allen, that the Earl was going to kill them and telling them to run away. Still he is a lonely person, stating that he would rather do things on his own if he doesn't have to use others.
He is a proud individual, deeming that he is the only one who can choose who is his family and who is his ally. He has also shown to be quite touchy as he attempted to activate his innocence against Tyki when the latter annoyed him while he was only going to visit the earl at first.
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She adopted the two babies and gave them the name of Nea and Mana. She raised them as her own children in the Campbell Residence. When Mana became sick he got very worried for him.|}
Nea and Mana grew up together and were very close.
Thirty-five years prior to current events and seventeen years afterwards., Nea, in order to become the new patriarch of the Noah Family, attempted to stop the Family and the Millennium Earl's plan to wipe out humanity. At some point, the other Noah gave him the nickname "the fourteenth" out of spite. At this time the other Noah hunt him down and due to their empathy ability, he had absolutely no place to hide and rest. He lived in fear. During this time, he also locked the location of the Ark above Edo, making it impossible for the other Noah to change its location, although it remained otherwise functional. On the run, attempting to keep his brother, Mana, safe and ensuring his eventual reincarnation should he die. He requested that Cross Marian watch over Mana, promising that one day he would return from the dead.Before Nea died, someone who seems to be a matured Allen, told Nea that he would protect his memory. This same person taught him what is the Helix of Life and the natue of the Earl's power.  He succeeded in killing all the Noahs except Road and the Millennium Earl. After Nea died, Mana hugged his dying body. He finally reached the earl for a final confrontation, he approached Road while she was holding an unconscious Earl with Nea staring angrily as Bookman was watching secretly.
Nea was eventually killed by the Earl, driving Mana insane and leading Cross to begin to search for his reincarnated form.
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The Earl (Mana) devoured Nea and as so became complete once again. Made insane by his persona conflicts, The Earl chose to destroy his own face in order to forever forget that he is Mana and Nea.|}
Some twenty years later, he was reincarnated within Allen Walker, his adopted nephew.
Suman Dark's Fallen arc
After Allen is nearly killed by Noah Tyki Mikk, he spends some time unconscious, wandering around in his mind in a vaguely sketched, child-like form on a small, paved island in the middle of a body of water flanked with skeletal trees, with a white moon above and a black reflection of the same moon in the water. When Allen looks down into the water and sees the European Branch in shambles within it, Lenalee sitting on the rubble with his body draped across her lap as she cries, Allen reaches out for her, only for a hand to emerge from the water and take his. His form solidified, Allen tries to pull away from the hand, watching as the surface of the lake freezes over, demanding that the hand let him go. The ice cracks, a shadowed form (Nea, though this is unknown to Allen at the time) tells him "no, not yet...you can't", and immediately after Allen awakens.
Noah's Ark arc
Because of Nea's actions thirty-five years before, Noah's Ark, which the Noah Family has been using for years, is locked in place above Edo, Japan. Road and the Earl attempt to start a 'download' of the old Ark's information to make a new one, but Cross Marian intervenes at the last moment and sends Allen Walker into a special, white room within the crumbling Ark where a piano sits.
There, Allen sees the shadow of the Fourteenth again, the Fourteenth speaking to him this time and telling him he can use "his" Timcanpy and the piano, which the Earl does not know of, to pilot the Ark. When Allen tries to ask the Fourteenth who he is, he does not receive an answer, Nea simply continuing to smile at him. As Allen begins to play, recognizing the crest and musical 'notes' Timcanpy is displaying for them, the Fourteenth explains that the notes are a song within Allen, encouraging Allen to "hope" to get the Ark to do what he wants it to.
Invasion of the Black Order arc
After appearing in the Ark, Nea begins to appear in his "Fourteenth shadow" form in every reflective surface Allen encounters, throwing Allen off at first before he starts to accept his presence, rationalizing it by thinking of Nea's shadow as being like something of the souls bound to Akuma, something only he can see.Lvellie reveals to Komui Lee that he found the will of the fourteen in an old man's house.
Destruction of the Black Order arc
While packing up the things within the European Branch and preparing to move to a new location, Allen reflects on whether or not Mana loved him or if the man was just using him, willingly looking at the Fourteenths reflection in a mirror as he thinks about Mana telling him (Allen) that he loves him.
Disappearance of Cross Marian arc
Nea's old ally and Allen's master, Cross Marian, eventually chose to reveal that Allen is the host for Nea's rebirth and that he is the brother of Allen's adoptive father, Mana. This revelation ultimately resulted in Allen being placed under even stricter observation, with the Black Order preparing to execute him should Nea overtake his consciousness.
Phantom Thief G arc
During battle, Allen deliberately impales both himself and a Level 4 Akuma with his Sword of Exorcism. Because the sword only harms evil things (namely Akuma and Noah), Allen believes that he will not be injured, but begins to cry out in agony as it attempts to exorcise the Noah memory within him. Nea awakens briefly, using the Akuma to call out to the Millennium Earl, but quickly falls back into Allen's subconscious after Yu Kanda calls Allen by a much-detested nickname, "beansprout".
Despite the fact that Kanda is obligated to report any signs of the 14th's awakening, Kanda does not mention the event to anyone and Allen remains unaware of his momentary lapse of control.
Artificial Exorcists arc
While recovering from the injuries his Sword of Exorcism inflicted upon him, Allen has a dream of Mana, and when he awakens Nea is in control of his body. Nea retreats, though, when a nearby Lenalee Lee calls out to Allen, who saw the look on Allen's face but doesn't comment on it, believing that she just imagined it.
After Allen and Yu Kanda are abducted by the Noah Family and brought to the North American Branch, the Earl speaks to Nea, taunting him into appearing by asking about when Nea used the Level 4 to communicate with him. Nea takes over Allen's body and confirms that he did, indeed, use the Level 4 to call out to the Earl, saying that he wanted him to know that he was back and that he would be coming to kill the Earl so he could take over the title of the "Millennium Earl".
Later, when Kanda impales Allen with his Anti-Akuma Weapon, Mugen, the damaged caused by the Innocence forces Nea's Noah side to react to the pain and take over Allen's body once more.
While Allen is unconscious, Nea meets him in his mind, keeping Allen chained to an odd, throne-like chair with wings as he comments that the Earl has become a mad puppet of destruction. He then comments that Allen also became an insane puppet before introducing himself by name to Allen.
Outside of the area, Timcanpy activates a spell that forces a barrier set up around the North American Branch to explode, which allows Allen's suppressed Pentacle Eye to activate and force Nea back yet again.
Seed of Destruction arc
Fearing that Nea will consume Allen's consciousness and accusing Allen of treason, Allen is imprisoned by the Black Order. During this time, Allen is barely conscious. Nea attempts once more to overtake Allen's mind, but the sudden presence of danger as posed by Apocryphos gives Allen the strength to push him back. Sensing that his 'brother' is in danger, the Millennium Earl sends Tyki and Road to protect Nea's host.
Searching for A.W. arc
As Allen is briefly reunited with Kanda and Johnny after three months, he flees from the arriving Akuma. After being taunted by Wisely and Tyki, Nea begins to resurface in Allen. Allen finally breaks and fall unconcious. He is carried to an inn by Johnny and Kanda. While Kanda it out, Nea awakens in Allen's body and impersonate Allen in front of Johnny.Timcanpy appears to recognize his master and lands on his face. Nea feels pain where Apocryphos hit him, and sees the feather-like substance on his chest with stupor. Johnny gives him some water and Nea thanks him. However when Johnny turns his back, Nea knocks him out. Nea is surprised with Allen's body, commenting on his "white" face and his notable scar. Nea looks to Timcampy and says, "Tim. Tell me about Allen." Timcampy then shows Neah Allen's life then he becomes upset and reveals a flash back of himself with the sword of salvation identical to the Earl's. A man that looks just like Allen was in front of him, saying that he'll protect his memory no matter how long it'll take. Then asks himself the question why Allen doesn't remember him. He is soon discovered by Kanda, where he is questioned as the 14th.
However, five minutes before Kanda arrived, Nea was watching Allen's memories from Tim, and became frustrated over Cross leaving him alone and wonders why Allen doesn't remember him. He says since it really has been 35 years, and he wonders why Allen's body hasn't become older, but rather younger and is shocked to see Allen's left arm with Innocence, and recalls when he met Allen when he was a young adult, promising him he would look after Nea no matter what. He tells Allen now they are enemies, and will not hesitate to gain his goals, and tells Tim not to tell anyone about what happened and from now, on he'll see things from Allen's eyes, and tells Tim to show him bits of him from time to time and when Allen dreams he will dissipate. He says this is his last journey, and now he must fulfill his promise to Mana. As Kanda has Mugen at his throat, Nea switched back with Allen already.
As Allen senses that Apochryphos is near and makes a run for it, The Earl appears before him in an alley, calling him "14th..." He then takes out a balloon and blows in it and attempts to crush Allen with it. He then mutter's Nea's name constantly and displays a far more deranged look as his appearance becomes much more larger and crazier. He asks if Nea recognizes him and as he continues to attack Allen, his face begins to come apart revealing his Noah form inside and looks at an unconscious Allen and almost crushes him as Johnny saves him. He sees Johnny try to take Allen away after seeing a similarity with Mana looking over Nea asking the Earl why did he do this. The Earl's human form then cries asking who Johnny is and angrily throws him to a wall. At that moment, the Earl and Allen seemingly lock minds causing Allen to see the Earl killing Mana's mother calling him "Mana D. Campbell" and he brought upon this tragedy. As Allen questions what he just saw, the Earl then remembers about Mana and shouts that Mana is the cause of everything. Millennium Earl then hugs Allen, after Nea takes over and is shocked by Nea's explanation on why he cared for Nea so much. Nea reveals to the Earl that he is actually Mana and that they weren't twins at first but actually the Millennium Earl himself, two parts of one whole.
Then Nea says that eventually the Millenium Earl returned to the "one" they used to be as his current self, when Mana devoured Nea 35 years ago. But Earl still can't understand what Nea is talking about and why he calles him Mana all over again. Nea adds it's fine even if Mana isn't able to remember this, because he still can destroy Mana. Just as Nea apparently prepares to do so, the finders of the Black Order, who were tasked to capture Allen, interfere in the sutuation and restrain him with the talismans.
While the finders ask him to surrender, Nea wonders if he didn't notice them because of his new body he's not used to yet. When one of the finders hustles the Earl without realising his identity, Nea tries to warn the finders to get away from him. However, the Earl already manages to attack Danny and destroy his body. The remaining one, Eams, is shocked and thinks it was Nea's doing, but Nea replies that it wasn't and repeats that he should run away. After Eams realises that it's the Earl himself, Nea repeats his advise, which he tries to follow, though eventually falling victim to the Earl too, with Nea calling him an idiot. The Earl tries to desintegrate Nea as well and wonders what they were talking about, while Nea recalls the words of his old friend about "the helix of life" which contains the souls themselves and possesses the great power capable to bring on the life's potential. Nea realises that the Earl devours nothing but the human souls and asks the Earl (calling him Mana) if he's going to devour him again. Nea is astonished when the Earl denies he's Mana, but claims to know where he is. Although the Earl declares that Mana is left in the place he can never return from, Nea comments about his bad jokes for a clown and argues that "Mana" who found and spent the years with the kid "Allen" was really him. The Earl continues to deny his identity as Mana and is about to finish Nea off for good with more tendrils, сalling Nea a nuisance.
Before the tendrils could reach Nea, several needles manage to stop them, surprising Nea. He sees the shadowy figure, which turns out to be Howard Link, who asks the Earl to move away from Nea. The latter remebers some details on Link as a CROW and wonders why he's still alive, albeit unable to remember his name right away. Nea is also impressed by the power of the spell capable of restraining the Earl Link casted on him. However, Nea is suddenly binded as well and brought on the roof of the nearby building along with Johny.
While Link appoligises to him for the roughness and notes that since he can't hold off the Earl for very long, they should run, Nea, unsure about Link's true intentions, pretends to be Allen and voices his relief about Link being alive. Link takes a close look on Nea's wounds and heals them with his Attuda golem, which Nea notes to be an opposite of the Earl's soul absorption transferring Link's his own life power to him. Then, Link asks Nea to stop acting like Allen because he can feel Nea's cold and murderous aura completely different from the real Allen. Although Nea tries to object he's Allen, he desides to throw away his disguise, stating that Link is a sharp human and seems to be a problem that should be eliminated. He adds that it's already too late for saving Allen if he came for this.
However, Nea learns that Link was send here by Lvellie to aid him, the 14-th, thus asking him to use his (Link's) life as he wishes, which prompts Nea to call him "scary". When Link directly states that Nea, as a person who already died, but managed to take over the alien body to came back in the present time, should be considered even scarier tham him, Nea, enraged by this comment, grabs him by the throat and says that it's actually scary to meet someone who came out of nowhere and asked to use their life. Also, he notes that in this world he hates humans the most and if he has Timcanpy by his side, it'd be already enough. Yet he's informed by Link that Timcanpy got gestroyed by Apocryphos, which shocks him. At the same moment, they are attacked by Feedler, who demands from Link to release the Earl from his bindings. During their clash, Nea is knocked back, wondering what's happening here. As he's feeling something, he returns back to the Earl who is taken into the Noah Arc by Wisely and Tyki. Nea parts with the Earl, stating that the next time he'll be the one visiting him in order to kill him. Tyki steps in to protect the Earl, while Nea seems surprised to meet him. Nea is troubled by Tyki's face who is familiar to him.
Wisely and the Earl then disappear through the Arc, and Nea parts with the latter with a smile on his face holding a hand to the earl while the earl himself holds a hand before disappearing. Tyki stays behind and voices his interest in meeting Nea, offering him to go back, eat a dinner together as a family and talk about "what" he is. Nea expresses his annoyance about everyone calling him the 14-th, including Tyki and Link, a nickname received from the previous Noah generation. He announces that his actual name is "Nea D. Campbell", and it's up to him to decide whom he considers his family or allies, rejecting both Tyki and Link's offers. Also, he comments Tyki's offer to eat together that Joyd's current form could make him laugh and spill out the food. At the same time, he tries to activate Allen's Innocence, despite Link's warnings that it's too dangerous for him as a Noah to do so. Nea ignores him, mockingly thanks him for his concern and goes on trying to activate the innocence with a confident look. When Link prepares to stop Nea by force, the newly awakened Johny calls out to him as Allen, though he realises that the 14-th is controlling his body now. Nea looks at Johnny, surprised before resuming an unfazed stare. However, Johnn's voice successfully reaches Allen, who manages to force Nea back into his subconsciousness and gain the control over his own body once again.
Abilities and Powers
Acting Skills: Nea has impressive acting skills, being able to perfectly emuate Allen's behaviour with only a few clues about his past and personality from Timcanpy. Link stated that he would be able to fool anyone and would have fooled him too if not for his own Ki sensing abilities.
Knockout: Nea has performed a technique to knock out Johnny Gill by striking with a quick blow on his neck, effectively rendering him unconcious for more than five minutes.
Natural abilities as a Noah: As a Noah, Nea is naturally gifted with abilities that only humans with the Noah gene within their bodies active are able to possess, including a natural command of Akuma, immunity to the Akuma blood virus, and the power to use Dark Matter.
Immense fighting and killing prowess: Even though his exact abilities are unknown for now, Nea was able to sucessfully kill eleven Noah who are all superhuman individuals with unique abilities. Him being half of the original millennium earl presumably gives him an enormous power.
The Pianist: He is also one of the three members of the family that have the authority to control Noah's Ark, the other two being Road and the Millennium Earl. Nea also has the power to pass on his abilities to use Noah's Ark to others, these powers referred to as being his "Will". Wile in Allen's body in Noah's Ark arc, he moved Allen's fingers and controlled the Ark.
Sword: Shown in one of the Flash backs, When The older Allen from 35 years ago, made a deal with Nea, He had the same sword that Millienium Earl uses today. (Could infer that when he killed Nea, he took his sword) 
Neah D. Campbell VS Noahs of the previous generation