Nelliel Tu

Several years earlier, Nelliel held the rank of 3rd Espada. During her time in that position, she was constantly challenged by Nnoitra Gilga to fights to prove that males are stronger than females. Nnoitra once laid waste to an entire colony of Arrancar, prompting Nelliel to ask him why as he was given no order to do so. Nnoitra stated that no one ever ordered him not to kill them. Nelliel reminded him that Aizen's order were to "seek the Vasto Lorde", she further explained that murdering entire colonies stood against that order. He responds that not everyone is loyal to Aizen and if they resist they are rebels and killing rebels is like helping Aizen. He further reasoned that if he can take them out then they are not Vasto Lorde, stating that he is following orders just fine. He then informs her that she has gotten awfully uptight over a couple hundred hollows. Nelliel suggested that he should think before he speaks, as they themselves were once Hollows just like those he killed; it was their own good fortune that they evolved beyond that, nothing more. Nnoitra taunts her to attack if she felt she could beat him if it made her mad. She plainly responded that she was shocked as even becoming an Arrancar, Nnoitra was nothing more then a child.

Nnoitra questioned her comment but is attacked and seemingly knocked unconscious. When he wakes up he sees she is sitting near him reading a book while a dead Hollow lies nearby. He asked her why she helped him, Nelliel simply tells him that she did not 'help him', she simply prevented the Espada from losing a member by putting an end to his suicidal behavior. Nnoitra explains that he can't stand her and she would obviously know that, asking why she keeps following him around. She simply stared at him and stated that its because he was weaker than her. Sometime later Nnoitra continued to kill Arrancar and Hollow alike, determining they were unfortunate for facing him. Nelliel noted to him that it was an Arrancar he just killed to which he responded he knew that and wanted to state as a fact something he would only explain once. Something he wanted her to know was that if she insisted to continually follow him around, then no matter who stood in his path, he would not be benevolent or merciful. Sometime later he challenges her to a fight to which Nelliel explains once again that she would not draw her blade against the likes of him.

Stating that he will not draw her into his demented world, Nnoitra told her that she was over thinking as the only reason they needed to draw their blades against each other was for the simple sake of drawing their blades. Nelliel noted that she did not understand that reasoning. She then asked what drove his blood lust. Nnoitra simply stated that gasping for his final breath in the heat of battle; to have his entire being defined by that moment was his greatest desire. Nelliel questioned this philosophy, noting that it would be a temporary high. He agreed to the truth of that but stated that nothing else could fill that void. He was given power and he would use it kill anyone standing in his way until he died on his feet, taking in his last breath. During this time, Nnoitra would constantly challenge Nelliel to battle, each time she would easily defeat him. It was during one of these battle she went to leave and he told her that it was a battle to the finish. When she asked him if he wanted her to finish him off, she told him that she simply refuses and further said him to stop talking all big.

She stated that there was a time when they ceased being Human, and became beasts. Now, as Arrancar they had regained their sense of reason. She explained to him that rational people, when going to battle need a reason to fight and he had none. Nnoitra screamed at her that he had a reason, he could not stand her. Nelliel detailed that it wasn't a reason just an instinct as he is a beast and she didn't recognize him as a warrior. Therefore she had no reason to bear the life of someone not a warrior. After Nelliel left, Nnoitra was approached by Tesra Lindocruz who offered him a hand. In response, he threw his Zanpakutō at him, hitting the structure behind the Arrancar. Nnoitra told him not to act friendly with him, and that just because he lost did not mean they were of the same level. When Tesra asked why he had to pick on Nelliel and no other Espada, Nnoitra explained that it was because he hated her, some female being able to outrank, be greater than a man on the battlefield; that was his reason.

Sometime later, Nnoitra teamed up with Szayel Aporro Granz (who was not an Espada at the time) to perform a sneak attack on Nelliel as well as test a device he created. As Nelliel was searching for her Fracción, she was confronted by Nnoitra, who asked her if she was looking for something. Nelliel stated it was none of his business and asked if revealing his weapon was a form of intimidation. She advised him to keep it concealed if he didn't want to look weak and moved on. There was an explosion which got Nelliel's attention. Once the smoke settled, she saw the her Fracción, Pesche Guatiche and Dondochakka Birstanne, gravely wounded. She turned to Nnoitra and asked him if he forcibly removed their masks as she became enraged. They initiated a fight during which a device made by Szayel created a fake image of Nnoitra and distracted Nelliel. By exploiting the opportunity, Nnoitra attacked Nelliel and hit her from behind, causing her a wound to her head and her mask to break on the front left side. The attack scarred her forehead and left her unconscious. He took her unconscious body and stated that she would probably call this an act of a beast but it didn't matter any to him. e was approached from behind by Szayel who asked if there was anything else to which Nnoitra responded that his job was already over.

Szayel asked him if he needed to be so cold as they had worked as partner and that he should at least be allowed to admire their end. Nnoitra detailed that he didn't remember being his partner and they just happened to have the same motives. Nnoitra threw Nelliel off the side of Las Noches so that he could increase his power by the time she returned. Nnoitra told Szayel that they were going, but Szayel told him that he would appreciate if he lost the presumptuous tone. Nnoitra snapped back that he wasn't even an Espada. Szayel stated that if not for the equipment that he prepared, Nnoitra wouldn't even have had the chance to attack Nelliel. Nnoitra then asked if he should really be speaking to him that way. He looks over the side of Las Noches at Nelliel and her Fracción prone bodies and was surprised as she had reverted into a child. Szayel noted that he had not anticipated this and he had never seen anything like it before. He deduced that her Reiatsu was leaking out of the wound on her mask, shrinking her spiritual body as a result. Afterward, Pesche and Dondochakka vowed that they would protect this newly weakened Nel at any cost. They took the roles of her playful older brothers, never revealing to her their true identities or her own identity for fear of her memories coming back. According to Pesche, this was because she had always hated fighting, and in her child form she was spared from it.

Hueco Mundo Arc
Nel is first seen being chased by Pesche Guatiche, Dondochakka Birstanne, and Bawabawa. While Ichigo Kurosaki, Yasutora Sado, and Uryū Ishida are running to Las Noches to save Orihime Inoue, they come across Nel and think she is a young human being chased by three hollows. After Ichigo and his friends attack the three, Nel yells at him to stop being mean to them. Ichigo then realizes that Nel is actually a Hollow herself and not a Human. They all then apologize to Ichigo and his friends because they didn't think their game of "eternal pursuit" would cause such a misunderstanding and they all introduce themselves. Nel tells Ichigo that Dondochakka and Pesche are her brothers and Bawabawa is their pet. Ichigo is confused by this as he's never heard of Arrancar having siblings. Dondochakka explains that he just found Nel lying around and that he just had to become her brother. Everyone then decides to ride Bawabawa to get to Las Noches faster.
On the way there Ichigo questions if they are really Arrancar since they have a different feel then the ones he met in the human world. Nel explains that the ones who went to the Human world were Numeros, who are Arrancar who are at least as strong as Menos Grande. She continues to explain that they are ruled by the Espada and are combat experts who are "filthy bugs". She then notices that Ichigo is not like an Arrancar either because of his lack of mask and black clothes. Ichigo then tells her he's a Shinigami and that causes to Nel to panic thinking that they will all get killed if they go to Las Noches. All of a sudden Runuganga, the guardian of the white sands, appears and confronts Nel and her friends.

Runuganga explains that he got information from Las Noches about people invading and that Nel joining with them is unforgivable and Nel tries to explain that she isn't with them. All of a sudden, Ichigo uses Getsuga Tenshō and splits Runuganga's head in half. Ichigo believes he's won, but Runuganga gets back up and brings his head back together. Nel explains that he is all of the sand in the area and that he can always come back together. Ichigo, realizing he can't be beaten, decides to escape and think of a strategy. Runuganga says he won't allow that though and forms a massive pit in the sand that starts sucking them down. Ichigo asks Nel if he has a weakness and she explains it's water and he asks where their going to find that. All of sudden a huge blast of ice comes and completely freezes Runuganga. The ice breaks and kills Runuganga. Ichigo looks to see who did that and finds Rukia Kuchiki and Renji Abarai. Ichigo jumps off of Bawabawa and goes to meet Rukia and Renji. Nel is panicked by this continuing to think that Shinigami are bad. Ichigo returns with Rukia and Renji and they begin riding Bawabawa again. They eventually make it to the side of Las Noches and break into the palace with force.

Ichigo and his group break into Las Noches and split into five directions, leaving Nel and her brothers behind. The siblings decide to follow Ichigo but get lost. Nel is the only one who catches up to Ichigo, arriving just in time to be confronted by Dordoni Alessandro Del Socaccio, a Privaron Espada with a number of #103. When Dordoni tries to fire a Cero blast at Ichigo, Nel steps in, absorbing the blast and firing it back. Enraged, Dordoni attacks Nel, who is then saved by Ichigo. Ichigo apologizes to her for holding back his power, which caused her to step in and get hurt. Dordoni then makes an attempt at attacking Nel further to goad Ichigo into using his Hollowfication. Outraged Ichigo places Nel down and Hollowfies attacking and defeating Dordonni with ease, as Nel looks on. Dordoni later wakes up to a drooling Nel who is using her "saliva" to heal his wounds. He then explains to Ichigo and Nel why he has faced them and then goes to attack them again even though he has already lost. Ichigo swiftly takes him down and leaves with Nel.

During her trip further into Las Noches with Ichigo, she witnesses his clashes with Ulquiorra Cifer, the 4th Espada and Grimmjow Jaegerjaquez, the 6th Espada.
After Ichigo finishes off Grimmjow, they are suddenly attacked by none other than Nnoitra Gilga, the 5th Espada. As they fight, Nnoitra notices Nel, recognizes her stating she has become pathetic and asks if her broken mask aches. Ichigo then questions how does Nnoitra know Nel. Nnoitra explains that he wondered why she was here figuring Ichigo brought her but states he realizes now Ichigo brought her not knowing who she really was. Ichigo is confused not knowing what Nnoitra means so the Espada explains that she is Nelliel Tu Odelschwanck, an ex-Espada. Nel tries to deny the accusation prompting Nnoitra to step on her but Ichigo blocks the attack and while Ichigo is telling Nel to not worry, he is kicked himself and is sent flying. Nnoitra comments that it does seem as though she has lost her memory, but after getting her head broken its no wonder she has forgotten all that has happened. Ichigo questions what does he mean broken, Nnoitra explains as he picks Nel up by her head that he is the one broke her head. Ichigo yells at him to stop and becomes enraged charging at him but Nnoitra counters only for Ichigo to get in close and slash him down the center of his chest. But Ichigo then realizes his blade has made contact but has done nothing. Nnoitra asks if he has already forgotten that there is no way he can cut him with that blade. He then kicks Ichigo again sending him further away, explaining that Nel always made him mad just like Ichigo is doing right now, thus why he broke her head from behind and threw her out of Las Noches. Ichigo screams at him to let her go and rushes to attack him but Nnoitra counters and throws Nel away in the process. As he goes over to a wounded Ichigo he states that its time to end this as he grabs Ichigo's sword arm and breaks his wrist. Seeing Ichigo hurt triggers Nel's transformation into her original form much to Nnoitra's surprise.

Nnotira states that she has returned to her original form. Before he realizes it she uses Sonído to move Ichigo to a safe distance away from him. After a small talk with Ichigo who reassures her they are still friends, Nel resolves to face Nnoitra. Though Ichigo is uncertain at first, it is revealed her former rank as 3rd Espada. Nelliel rushes to attack Nnoitra and cuts him across the chest before he can react, surprising him entirely. He tries to attack her but she effortlessly kicks his Zanpakutō away, pushing him off balance and sending him a distance away from her. He eventually stops himself and fires a Cero at her, causing Ichigo to scream out trying to warn her. Nelliel simply places her hand up stopping the blast entirely much it Nnoitra's surprise. She then sucks the entire blast into her mouth fires a Cero Doble at him causing a large explosion. Tesra lets Orihime go as he runs off to aid his master but no sooner than he does that he is sent flying away into nearby debris. Nnoitra appears injured along his right side, asking Tesra who told him to let go of that woman to which he apologizes. Nnoitra smiles at Nelliel and asks what is wrong, he was hit by a Cero that she absorbed and then added her own to it... so why is he still alive? He notes that her face is asking that. He then admits that he forgot about her Cero Doble, her trademark technique. He then explains to her that she doesn't get it as she has forgotten one thing. Since she left Las Noches, he asks her how many years have passed since she disappeared? He then states that she shouldn't think the power of the current Espada is the same as when she was an Espada and that the number on her back is meaningless now.

The two Arrancar continue to battle with both facing each other evenly. As they fight Nnoitra asks if she remembers calling him a beast and even saying their strengths weren't even. He then gloats asking how does it feel being beaten to death by the same beast. Nelliel then kicks his Zanpakutō away as Nnoitra goads her, Nelliel tells him its such a pity as it will be difficult to transform again after only just returning to her original form. Therefore she didn't want to resort to it, and she begins to release her Zanpakuto. Nnoitra realizing what she is doing moves to stop her but isn't fast enough and is forced back by the release of reiatsu. He is quickly overwhelmed as Nelliel uses her "Lanzador Verde" technique which he tries to stop with his Zanpakutō but the attack succeeds on getting through regardless slamming him against a slab or rock. Nelliel goes to Nnoitra and tells him that its over but he should not despair as she will not take his life. In an instance she reverts back into a child to everyone's surprise. Nnoitra steps on her and laughs then kicks her prompting an enraged Ichigo to attack again, only to be slammed into the ground. After getting bored with fighting Ichigo he commands Tesra to finish him off, to which Tesra releases his Zanpakutō and proceeds to beat Ichigo mercilessly. Nnoitra then forces her to watch as Ichigo is brutalized. She is soon healed by Orihime when Kenpachi Zaraki arrives to fight Tesra, then Nnoitra. It can be assumed she might have regained her memories yet again as she locked eyes with Nnoitra and says his name as he dies. But when Coyote Starrk suddenly appears to kidnap Orihime, she remains on the battlefield as Ichigo leaves to rescue her.