NELLIEL TU ODELSCHWANCH

Nel's appearance is in stark contrast to her vocabulary, which contains a number of bizarre phrases and words one wouldn't expect such a small child to know, such as calling her uvula a "throat penis" and referring to herself as a masochist. Ichigo Kurosaki assumes her Hollow companions are responsible for this. During her group's super sentai intro she prefers the name "Thieves: Nel-Don-Pe." She also seems to speak with a lisp in her child form, frequently pronouncing "S"s as "T"s. Nel and her companions also represent oddities among Hollows; though most Hollows are evil, Nel actually fears Shinigami, assuming that they are, in fact, the evil ones.

Despite believing that Shinigami are evil, Nel develops an attachment to Ichigo and follows him into Las Noches. And when she returns to her physical form, despite growing up physically, she somehow retains her child-like affection over Ichigo, best-shown when she unexpectedly bear-hugged him after attacking Nnoitra without realizing that Ichigo was losing consciousness (although the anime's flashback of Nel's accident suggested that she was always somewhat childish outside of combat). 

As Nelliel, she is much more mature, composed, logical, sophisticated, and intelligent than her child form. She is also relatively level-headed in terms of how to fight, stating that if one's excuse for a battle is to fight out of hatred, prejudice, or simple competition, as Nnoitra does, then it is merely instinctual and animalistic, and that it makes the challenger look "childish," "unworthy," and "not much of a warrior". Though Nelliel has proven during her last few minutes as a full-fledged Espada that it is 'acceptable' when it involves vengeance, she does not view even that as a reason to fight. Unlike many of the Arrancar, Nelliel is somewhat pacifistic, and according to her Fracción, has despised engaging in combat even when she was still among the upper ranks of the Espada, unless it involves self-defense and protecting those dear to her heart. It is for this reason that Pesche and Dondochakka decided to simply be content with her child form and banished themselves from Las Noches. She refuses to finish off weaker or injured opponents, and will stop fighting them once they've been disabled or incapacitated, a trait shared with Kenpachi Zaraki. 

As witnessed during her numerous fights with Nnoitra, Nelliel's shown to be relatively calm and silent when fighting, preferring to speak only when spoken to, a rather uncommon trait among most Arrancar. She is even shown to enjoy reading, usually seen reading a book after her missions or after waiting for Nnoitra to wake up after their recent battle.

Nelliel's also shown to be a loyal, respectful, and trustworthy warrior, who will diligently follow the orders of her commander, provided said commander has proven his worth. She's also knowledgeable, analytical, easygoing, fairly compassionate (usually towards her friends), humorous in her own right, and exhibits a cheerful, energetic demeanor when off-duty.