Nea D. Campbell/History

History
Nea appeared as a newborn, alongside his twin brother Mana, under Cornelia in the Campbell Residence when the Earl of Millennium vanished in front of Katerina Eve Campbell. She adopted the two babies and named them Nea and Mana, and raised them as her own children in the Campbell Residence. Nea and Mana grew up together, and were as close as can be and overall seemed to lived a happy childhood.

About thirty-five years prior to current events, when he and Mana were seventeen years old , Nea, in order to become the new patriarch of the Noah Family, attempted to stop the Family and the Earl of Millennium'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 hunted him, and due to their empathy ability, he had absolutely no place to hide and rest, so he lived in constant 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 nature 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. 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 unconscious. 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 calls 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 situation 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 revealing 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 realizes 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 disintegrate 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 realizes 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 remembers 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 Johnny.

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 decides 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 than 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 destroyed 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 14th, 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.

Nea comments on Tyki's offer to eat together that Joyd's current form could make him laugh and "spit out the food that he ate." 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 Johnny calls out to him as Allen, though he realizes that the 14th 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 control over his own body once again.