Kalluto Zoldyck

Kalluto Zoldyck (カルト, ゾルディック, Karuto Zorudikku) is the youngest son in the Zoldyck family.

Appearance
Kalluto has a shoulder-length black hair and purple eyes. There is also a noticeable mole near the side of his mouth. Kalluto's most commonly seen attire is kimono. When he was first introduced, he wears a long red kimono, a yellow obi tied around his waist, and a pair of slippers. During the Yorknew City and Greed Island arcs, Kalluto's kimono was changed to blue with snowflakes and a yellow obi.

Personality
Kalluto has a silent and obedient personality, often seen doing what he is told. During the first part of the series, Kalluto doesn't mention more than six words. He also has a habit of questioning his abilities, if he is not good enough. It is later revealed that he can be a bit of a masochist during his battle with a Chimera Ant and he says that he is used to enduring the pain. While he has a very good relationship with his mother, he is said to be envious of his older brother Alluka, for some reason that has yet to be revealed.

Zoldyck Family arc
Kalluto first appears spying on Gon in the bushes, as the latter attempts to pass Canary's guard. Kalluto silently watches as Kikyo tries to convince Killua that his friends will never open the Testing Gate. Before Kalluto and Kikyo leave Gon and his friends, Kalluto asked Gon who he is, and he replies that he is Killua's friend. Kalluto gave him a curious look then ran after his mother.

Yorknew City arc
Kalluto appears again in the Yorknew City arc, in which he and his great-great grandfather Maha assist his big brother Illumi in the assassination of the Ten Mafia Dons who have placed large bounties on the Phantom Troupe's heads. He later acts as a decoy to help Illumi switch places with Hisoka in the Troupe's hideout — Hisoka has hired Illumi to disguise as himself so that he will be able to leave without being noticed and fight Chrollo.

Greed Island arc
During the time the Phantom Troupe is on Greed Island in search of an exorcist, Kalluto is introduced again, this time as Hisoka's replacement, and it is his abilities that helped them successfully find the exorcist, Abengane. Even though he has a perfect Zetsu, his presence is still detected by Hisoka, who goes on to praise him for having a lot of potential.

Chimera Ant arc
During the Phantom Troupe's assault on Zazan's palace in Meteor City, Kalluto fights a chimera ant, which he kills after torturing it for a while. It is then revealed that he joined the Spiders with the intention of bringing back an older brother of his. He anticipated that he would rise to the number 2 position in the Troupe very quickly, but is left in awe of the Phantom Troupe's combat proficiency and has to admit to himself that his own skills are still too lacking compared to theirs to achieve that objective.

13th Hunter Chairman Election arc
Although Kalluto doesn't formally appear in this arc, he was shown in a short flashback of Killua when he was still a child. Kalluto, along with his older brothers Milluki and Alluka, are out for a walk when they met a photographer. Milluki tricked the photographer Muuna into saying 'No' to Alluka's wishes 3 times. Later, it was also stated that Kalluto is envious of his older brother Alluka.

Combat
As a Zoldyck child who often participates in his family's assassination missions, Kalluto probably possesses high resistance to poisons and electricity, great agility and physical strength, and advanced assassination techniques. He can manipulate his paper confetti with accuracy through swift movements of his fan.

Enhanced stealth: Kalluto is very proficient in hiding and spying: he watched over Gon, Kurapika and Leorio completely unseen. He was able to appear before Bonolenov and Franklin without them noticing him approaching, and to disappear in seconds, something neither Gon nor Killua, a very gifted assassin himself, managed to achieve. Only Hisoka was able to sense him, but still praised his competence in Zetsu. Again, in the nest of the Chimera Ants lead by Zazan he applied Nen-imbued confetti on his fellow comrades and followed their actions through his Surveillance Paper Dolls undetected.
 * Rhythm Echo: Like his brother Killua, Kalluto can execute the Rhytm Echo, as shown in his battle against the stag beetle Chimera Ant. It is unknown who is the most skilled out of the two. The Rhytm Echo is an advanced assassination art, thanks to which the user creates several after-images of his body through a varying cadence of steps. There is a total absence of noise during the movement. According to Netero it is the advanced version of the "silent gaits" technique. When Kalluto used it, he left at least two after-images behind himself.

Higly proficient in Tessenjutsu: Kalluto is fully capable of fighting with his paper fan: he demonstrated it by slicing a steel rope three times before it was able to reach him. The current produced by the motion of his fan is strong enough to negate attacks launched with said rope.

Nen

In the field of Nen, Kalluto has the ability to manipulate paper, using a paper fan and confetti as weapons. He seems to be fairly talented, as he learned it before Killua and Gon. His skills were such that he was allowed to join the Phantom Troupe very young, though he considers himself one of the weakest members. Kalluto has showcased impressive skills in Shu and Zetsu, the latter of which caused him to be praised by Hisoka.

Trivia

 * There is a relatively common misconception that Kalluto is female. Despite wearing a kimono, typically a traditional dress for Japanese women, Kalluto is a boy:
 * In the manga, Kalluto has referred to himself using the normally masculine pronoun boku (ぼく or 僕) multiple times.
 * In chapter 323 of the manga his older brother Milluki calls him 'younger brother.'
 * The 2004 data book seems to say that he is a boy with the tidbit: 「将来性豊かな着物少年 (!?)」 (lit. A kimono-wearing boy (!?) with a lot of prospects.)
 * During his infiltration with Illumi in the Spiders' hideout, Franklin refers to Kalluto as a he, although in the manga, he used the prounoun she.
 * It is unclear who the brother Kalluto refers to is, though it is possible that the person in question is Killua: that would also explain Kalluto's envy towards Alluka, who is loved by Killua.
 * He has the same voice actress as Neon in the 1999 anime adaptation.
 * According to the manga's creator Yoshihiro Togashi, Kalluto's design was inspired by Hotaru Tomoe from Sailor Moon.
 * He resembles Ai Enma from Hell Girl, in which both characters share the same voice actress in the 2011 anime adaptation (Mamiko Noto).