|He's inside of me too. And you, Kaya. And everyone. There's a devil inside of us all... and that's why the world turned out this way.|
|— Niccolo's belief that everyone has the capacity for evil|
Niccolo (ニコロ Nikoro?) is a former Marleyan soldier who served on Marley's Navy and was part of the first survey fleet to Paradis Island after the failed Paradis Island Operation. After being taken captive, he begins working on the island as a chef for the military.
Niccolo is a young Marleyan man of short stature and slim build. He has a petite pointed nose and is blond, with his hair falling to the sides, looking like he has an undercut. He wears the standard Marleyan military uniform.
While visiting the cemetery, Niccolo wears a black suit and tie.
Niccolo was at first a very typical Marleyan, fearing the Eldians of Paradis Island and calling them devils. He was very disgusted with having been captured by them and having to live by their side, but after spending a lot of time with the Survey Corps, he and his comrades have developed a grudging respect and shaky friendships with the ones they once thought of as devils.
Niccolo seems to be somewhat courageous, disregarding his own life to beg his fellow soldiers to kill the islanders despite being held at gun point by them. He is also shown to be willing to risk ruining his relationship with his friends in order to keep them safe, deriding Connie Springer and Jean Kirstein for their Eldian status in an attempt to keep them from drinking wine laced with Zeke Yeager's spinal fluid.
Despite this, Niccolo had demonstrated a vengeful side: upon learning of Gabi's identity as Sasha's murderer, he went into a raging frenzy, punching Gabi in the face, bringing her in front of Sasha's family and offering Mr. Blouse a knife to kill Gabi, stating that he would do it if Mr. Blouse did not. Furthermore, when the other soldiers arrived, Niccolo grabbed the knife and held it to Falco's neck, telling everyone to stay back. However, after hearing Mr. Blouse's speech and his willingness to forgive Gabi, he immediately felt great regret for what he did, and was inspired to become a better person as a result.
As a member of the first survey fleet's advanced party, Niccolo arrives at Paradis Island ahead of the main Marleyan vessel. Sometime after being captured, the Attack Titan seizes the main vessel. Hange Zoë and Levi Ackerman threaten Niccolo with a blade in an attempt to make the navy soldiers comply. Despite being in danger, he screams for his naval captain to shoot the islanders.
On one occasion later in the year, Niccolo cooks seafood for those working on the port. He is surprised by Sasha Blouse's impassioned reaction to the new style of food. He and Sasha eventually grow closer, developing a more intimate relationship. Niccolo would later credit Sasha for instilling in him a belief that he should use his cooking skills to bring people happiness, claiming that she "saved" him from the Marleyans' war with Eldia. Niccolo is later approached by Yelena and is told by her to serve the wine aboard the ships to all military personnel with an emphasis on the most high-ranked members; he agrees, but suspects something was done to the wine. Regardless, he keeps this to himself and does as told.
In 854, hearing about Sasha's death in Liberio, Niccolo attempts to visit her grave to pay his respects, but is harassed by a member of the Military Police because of his Marleyan status. Jean Kirstein and Connie Springer come to his defense, and Niccolo explains to them why he has come to the cemetery. Arriving at the grave, Niccolo asks to know how she died. Jean apologizes to him, blaming his own carelessness for Sasha's death, but Niccolo is confused as to why Jean is apologizing to him, pointing out that he was only their cook. He asks Connie how he is coping, but their conversation is interrupted by the arrival of Mr. Blouse and his family. After they have paid their respects, Niccolo introduces himself and offers to cook for them someday.
On the day that the Blouse family comes to eat at his restaurant, Niccolo is ready for them and greets them at the entrance and gives them a tour of the restaurant, before showing them to their table. As he is cooking their main course, Hange and several other officers from the Survey Corps arrive requesting a word with him. He shows them to a private room where he will be able to talk with them after serving the Blouses. As he is returning to the kitchen, Jean notices that the wine in the room is the kind reserved for the military elite and tries to take some, but Niccolo suddenly confiscates the bottle, claiming it would be a waste on lowly Eldians.
As he is returning the bottle to the wine cellar, Niccolo is confronted by two children from Blouse's group claiming to be warrior candidates. He demands to know how they got onto Paradis, and is mortified to learn that they were brought on the airship that returned from Liberio. He demands to know if they killed any soldiers on their way to the island, which Gabi confirms, and Niccolo flies into a rage, attacking her with the wine bottle. Falco protects her from the initial blow, but Niccolo proceeds to beat her before dragging the two of them upstairs.
Niccolo takes the two to the Blouse family, revealing to them that Gabi is the one who killed Sasha. He offers Mr. Blouse a knife to kill her with, claiming that he will kill her if Blouse does not. The stand-off is interrupted by the Survey Corps, but Niccolo keeps them at bay by threatening Falco. Gabi tries to talk him down, but her words only incense Niccolo to kill Falco in order to hurt her. Before he can, Mr. Blouse requests the knife, and Niccolo complies. However, to Niccolo's shock, Blouse gives the knife to his wife and announces that he will not kill Gabi. Lisa Blouse orders Niccolo to release Falco, and Niccolo sullenly complies. As Connie and Jean restrain him, Niccolo advises Hange to try to keep any wine from getting in Falco's mouth, revealing that the wine potentially has Zeke Yeager's spinal fluid in it.
He admits that he has no proof to back his claims, but informs them that the ships he arrived in were stocked with more alcohol than would normally be required, and recalls Yelena's order to serve the wine to the military's officials before anyone else. He reaffirms to the distressed soldiers that he is only theorizing, but notes that using Zeke's spinal fluid to create Titans has allowed Marley to conquer nations almost instantaneously in the past. When questioned by Jean, Niccolo refuses to admit that he stopped them from drinking the wine to protect them, claiming that what little information he had was to atone for his attempt to murder Gabi. As Niccolo is helping the Corps wash the wine out of Falco's mouth, they are taken captive by the Yeagerists, who have been tipped off to the officers' presence in the restaurant by another Marleyan prisoner.
Niccolo and the rest of the restaurant's patrons are brought to Shiganshina and placed in a jail cell together. While Niccolo is preparing tea, the inmates are visited by Yelena, Onyankopon and Griez. Niccolo theorizes that the Anti-Marleyan Volunteers are planning on taking over the island, before insulting Griez for allying himself with Yelena. Griez responds by accusing Niccolo of defecting first due to his infatuation with Sasha, before going on to insult her repeatedly. Niccolo becomes enraged, trying to attack Griez through his cell's bars, but their confrontation is brought to an abrupt halt when Yelena calmly shoots Griez in the head for behaving rudely.
After Shiganshina comes under attack from Marleyan forces, Onyankopon releases the prisoners from their cell, requesting that they join in the fight to protect Eren. Although the soldiers are distrustful of Onyankopon, Niccolo supports his claims that he did not know about Yelena's true intentions, informing them that he had been ordered not to tell any of the Anti-Marleyan Volunteers about the spiked wine. As the soldiers agree to join the battle, Jean orders Niccolo to keep the Blouse family safe.
The group is forced to flee their hiding spot after being found by a Titan. While fleeing, Kaya trips and Niccolo is forced to save Mr. Blouse from being devoured when the latter tries to save her. Kaya is saved from the Titan by Gabi, who informs the group that Falco has been captured. A group of soldiers locates them and Niccolo takes Gabi's anti-Titan rifle, claiming that he killed the Titan in order to protect her identity as an escaped prisoner.
While the soldiers escort them to the military's headquarters, Niccolo listens as Kaya and Gabi talk to each other. After Kaya and Gabi claim to be devils for all of their own former misdeeds, Niccolo consoles the two by telling them that everyone has a personal demon.
After the rumbling and the elimination of the Titans inside Shiganshina, Niccolo informs Armin that he will be staying with the Blouse family for the time being while preparing horses for him and Gabi so they can travel to Ragako in order to rescue Falco.
- Sasha Blouse - Niccolo was initially hateful towards Sasha because of her Eldian heritage, but he softened up after she complimented him on his cooking skills. After their meeting, the two gradually became closer enough for Kaya to believe they were in love. Niccolo credits Sasha with saving him from the war and teaching him that he can cook to make people happy.
- Mr. Blouse - Niccolo met Mr. Blouse at Sasha's funeral and immediately offers to cook for him and his family for free, and the two shake hands. When Mr. Blouse and his family come to his restaurant, he graciously accepts them, and upon learning of Gabi's role in Sasha's death, offers Mr. Blouse the chance to kill her, showing a degree of respect towards him. After hearing Mr. Blouse's speech, willingness to let go of his hatred and forgive Gabi, his respect for him only increases, stating he cannot be a man like Mr. Blouse yet, but attempts to atone for his actions in his own way.
- Gabi Braun - Niccolo holds a great deal of animosity towards Gabi for her murder of Sasha. Upon learning what she did he immediately attempted to kill her in a fit of rage. He was also very vengeful towards her, willing to kill Falco in front of her because he was potentially precious to her just as Sasha was to him. However, after Mr. Blouse's speech, his hatred for Gabi has practically diminished, as he went along with Kaya's lie to ensure Gabi was not arrested by soldiers, and when Gabi calls herself a demon, Niccolo consoles her by saying everyone has a demon within them.