Illumi Zoldyck

"I don't mind dying as long as it means the rest of my family will be safe... Killua will suffer for the rest of his life. And I will live on forever... in Killua's heart...!!""

- Illumi Zoldyck

Illumi Zoldyck (イルミ＝ゾルディック,  Irumi Zorudikku) is the eldest child of  Silva and  Kikyo Zoldyck and one of the main antagonists in the anime series Hunter x Hunter..   Illumi currently seems to be the only person that Hisoka claims as friend, although their relationship is unconventional.

Appearance
Illumi appears expressionless, his face like an emotionless mask. He has very long jet black hair, usually combed behind his head as well as, very large, dark eyes. To disguise himself as Gittarackur, Illumi uses large round head pins to reconstruct his facial structure, and even voice, beyond recognition. The pins in his chest seem to affect the muscles in his body, as he looks more slender without them.

When he was younger, Illumi's hair only reached his shoulders. He wore long sleeves with a shirt underneath, as well as grey pants.

Personality
Illumi, for the most part, displays very little expression. In contrast to his expressionless demeanor, Illumi often speaks in a somewhat joyful and absent-minded tone. He is generally a stony, ruthless person with an extremely cold way of thinking, reflects only his interest. Still, he holds a twisted and overprotective form of love for his younger brother, Killua, this manifests to the point that he used his Nen ability to control Killua and ensure he survives and obeys.

He and his father raised Killua to believe that the only thing sustaining him was darkness, and that he could only obtain joy in causing the death of others. To ensure that Killua would live to carry on the family business, and as a means of protecting his little brother, Illumi implanted a needle in Killua's brain, forcing the latter to run from battles he wasn't sure he could win.

He also has an unusual friendship with Hisoka, although it is unclear as to how it developed. Illumi once came to the aid of Hisoka by standing for him as a double in the Phantom Troupe's hideout while Hisoka attempted to find Chrollo. However, when Hisoka asked Illumi would it be okay if he killed Killua, Illumi displayed a horrifying side of himself and asked if Hisoka wanted to die then and there - he acted very similar to how Hisoka did himself after Illumi was opting whether or not to kill Gon, whom he sees as a threat due to his closeness with Killua, during the Hunter Exam, albeit on a much lesser expense.

Illumi cares for most of the Zoldyck family members. He is willing to handle Alluka's power, even if it costs him his life. He has stated, however, that family members are not allowed to kill during an inner mission (a mission where there is internal conflict), but insinuates that he would be fine with killing Alluka and does not consider Alluka a member of the family.

Tsubone implies that Illumi's sinister ambition to control Alluka's power even caused him to stray from the path of an assassin.

Background
Illumi is the eldest son of  Silva and  Kikyo, and was raised from birth in the art of assassination. He trained Killua to become an assassin. Illumi was sent by his mother to watch over Killua, who also entered the Hunter Exam. In order to control the development and actions of his younger brother, prior to the series Illumi inserted a needle into Killua's brain, forcing him to run away from the battles he wasn't sure he could win.

<span style="color:rgb(58,58,58);line-height:22px;">Abilities and Powers
<p style="color:rgb(58,58,58);line-height:22px;">Illumi has all the benefits granted by his status as a Hunter. Furthermore, as a member of the Zoldyck Family, he has vast wealth and capable underlings at his disposal. His family name alone is enough to scare the ones that know what it is associated to. Illumi has been trained since birth in assassination techniques. Hisoka rates Illumi's overall strength and Nen as 95 points, which makes him considerably stronger than some members of the Zodiacs.

<p style="color:rgb(58,58,58);line-height:22px;">Thanks to his training he possesses rare abilities such as strong resistance to poison, high tolerance to electricity, great agility and physical strength, and advanced armed and unarmed combat techniques. He was able to single-handedly wipe out a squadron of rookie and pro Hunters before any had the time to press the emergency button. He is also a very skilled impersonator. He might have superhuman control over his body, as he told Hisoka he was going to sleep for five days.

<p style="color:rgb(58,58,58);line-height:22px;">Enhanced Speed: While the true extent of Illumi's physical abilities is unknown, he is at least fast enough to run through a crowd and stick his needles into multiple targets without being noticed. His speed allowed him to kill a group of Hunters before any of them could ask for help.

<p style="margin-top:0.4em;margin-bottom:0.5em;color:rgb(58,58,58);line-height:22px;">Immense Tolerance to Pain: Illumi does not flinch when Gon breaks his arm; afterward, he exhibits no visible distress from the pain.

<p style="color:rgb(58,58,58);line-height:22px;">High Intelligence: Illumi is able to formulate accurate predictions as seen concerning Alluka's power, since he was able to completely understand the method in which Killua's wishes were granted with no further consequences. He has also foreseen Killua's movements from the moment he took Alluka to heal Gon, assuring his high deductive intelligence.

<p style="color:rgb(58,58,58);line-height:22px;">Master Thrower: Illumi can throw multiple needles with high accuracy, always hitting the target with their point, despite them not appearing balanced. He can even pierce rock-hard materials with them, possible due to some sort of emitted Nen being attached to the needles themselves, however it may be due to his sheer strength.

<p style="color:rgb(58,58,58);"> Nen: Illumi is a Manipulator, and has an incredibly powerful, murderous aura which makes Killua fearful and wary whenever he approaches him. It is unknown how he learned Nen before becoming a professional Hunter. He mainly uses it to alter his physical appearance, and can do either with or without the help of his needles, although the transformation lasts longer in the second case. This type of needles can also be used to distort other people's features and skeletal structure, seemingly causing them great pain, and manipulate the dead to some extent. When imbued with Nen and thrust in the target's head, his needles allow him to gain control over his or her mind, or to condition them into acting in a certain way, as he did to Killua. His aura is so powerful that, if injected in a normal person, it will cripple them for life. Illumi might have made a different use of Manipulation when he closed up a hole in the ground without apparently touching it, moving the soil with his Nen.

Quotes

 * (To Hisoka) "I will kill you. Right here, right now."
 * (To Killua) "Killing within the family of prohibited. But if you wish "it", that's different. Now then, are you ready to do me in?"

Trivia

 * The Official Hunter × Hunter Character and World Databook has spelled Illumi as "Yellmi Zaoldyck".
 * It was hinted that Illumi knew Chrollo Lucilfer before the Yorknew City arc started.
 * Illumi may come from an Italian word ("illuminato") that means enlightened, the opposite of Illumi Zoldyck's personality. However, his name may be related to the Illuminati, whose goal is to control the world. Illumi is also a Manipulator, which fits with the Illuminati's iconic description.