"Get serious, Hisoka. I'm not who I was two years ago."

— Kastro to Hisoka Morow, in "Double"

Kastro (カストロ, Kasutoro) was a prominent fighter in the Heaven's Arena and an apparent celebrity. He lived on the 200th floor of Heaven's Arena, with the intent of accumulating enough wins to become a Floor Master and winning a rematch against Hisoka.[1]


Kastro 2011 Design

Kastro 2011 Design

Kastro 1999 Design

Kastro 1999 Design

Kastro was a well-built man who had green eyes and loose white medium-length hair that reached down to his upper back. His dressing attire consisted of a yellow hood-less cloak over a white robe with black outline, and white pants that were tucked into his grey boots. In the 1999 anime adaptation, his design is identical for the very most part with the differences being his color scheme and the shortening of his cloak.


Kastro was shown as being both a calm and reflective man, but he may hold strong grudges towards those who had defeated him as he became really determined to defeat Hisoka after their first encounter ended in a loss for Kastro. His strong desire to win against Hisoka made him follow the wrong path, deciding to learn and over-emphasize other Nen categories and fighting styles that don't align with his natural Enhancer category as well as his true strength, which ultimately helped to cause his demise at Hisoka's hands during their second encounter.


Two years prior to the start of the series, Kastro fought Hisoka in the Heaven's Arena. He scored a knockdown and won three points (the only one to do so against Hisoka), but was ultimately defeated. After this, he trained rigorously to improve his Nen, and had gained nine wins, during which he had kept his Double ability hidden. Recently, he has challenged Hisoka for a rematch for his tenth win, confident that he could defeat him.[1]


Heaven's Arena arcEdit

Kastro makes his first appearance during an interview before his match with Hisoka. Interested in meeting Kastro, Killua manages to sneak past a guard and makes it to his room. As Killua spots Kastro sitting in his room, Kastro mysteriously appears behind him and inquires what his business is with him. Killua, baffled that the chair he saw Kastro sitting in was now empty, claims he wants an autograph. Although happy to oblige to the request, Kastro easily deduces Killua's true motives and foresaw his arrival, for using Zetsu upon entering the floor. Curious Killua inquires how Kastro managed to disappeared so quickly, but Kastro keeps it a secret. Kastro returns to his room, but not before saying he'll wait for Killua at Battle Olympia. Killua however has no interest in fighting him.[1]

Hisoka vs Kastro 2

Kastro wins the first point

Before the match with Kastro and Hisoka began, Kastro thanks Hisoka for baptizing him from their previous match two years before, because of his baptism he's accumulated greater strength, which is enough for him to beat him with. The referee begins the match and Kastro quickly gets the first hit. Surprised by this, Hisoka believed he avoided the attack as Kastro demands Hisoka to get serious.[1] Kastro claims he's not the same as he was 2 years ago and won't hold back any longer. Hisoka merely mocks Kastro about being serious. So Kastro takes another swing at Hisoka who dodges, but gets hit with another unforeseen attack. The unforeseen attacks continue until Kastro manages to knockdown Hisoka, gaining him a 4-0 lead. Regaining his composure, Hisoka claims to have seen Kastro disappear. Hisoka tries to deduce how Kastro managed to pull such a feat on him so far. Kastro however tries to instigate Hisoka to attack him and uses his Tiger Bite Fist Hatsu to rip off Hisoka's right arm, whom sacrifices it willingly.[2]

Kastro then taunts Hisoka for sacrificing his arm, stating that if he thinks this would act in his favor he's wrong. However Hisoka is confident it will and then uses a leg sweep on Kastro, while catching his severed arm in mid-air. Hisoka then proclaims that this whole time Kastro has been creating a Conjured double to help preform feint attacks. Kastro confirms Hisoka's deduction and has his 'Double appear next to him. After a brief conversation Hisoka and Kastro have of the strength and properties of Kastro's Double, Kastro then assumes the position of his Tiger Bite Fist again and proclaims he'll use his True Tiger Bite Fist to rip off his left arm. Hisoka however becomes excited by Kastro's declaration and starts to eat the flesh off his severed arm, irking Kastro a bit.[2] Hisoka then covers is severed arm within a cloth and makes said arm disappear, making a bunch of playing cards scatter across the arena. Hisoka then has Kastro pick a card and memorize it and after calculating a mathematical equation pulls an ace out of the severed part of his arm.[3]

Kastro killed 2011

Kastro dies

Agitated Kastro uses his double to take Hisoka's left arm, whom again willingly gives up. However Kastro is shocked to see Hisoka's right arm reattached and deduces that Hisoka used his Nen to reattach his arm. Hisoka then praises Kastro's skill, but predicts he'll dance himself to death. Aggravated, Kastro and his Double charge towards Hisoka, but as they separate Hisoka figures out the real Kastro, because the Doppelganger doesn't reflect any damage dealt to it. Frustrated by this reveal, Kastro tries to ambush Hisoka from behind, but is struck in the face by Hisoka's severed left arm. Stunned by the attack Hisoka throws his sharp playing cards at Kastro killing him on impact. Hisoka claims by squandering his memory to create a Conjured duplicate of himself that also can be controlled and use complex moves, Kastro caused a "Memory Overload", leading to his demise.[3]

When Wing teaches Gon, Killua, and Zushi about the individuality of Nen, he reveals that Kastro was an Enhancer. However since he chose to create a Hatsu using both Conjuration and Manipulation, which aren't compatible with Enhancers. Although he mastered this Hatsu through strenuous training, he overexerted his talent.[4]

Abilities & PowersEdit

Kastro demonstrated himself to be an excellent fighter with considerable combat skills, which many rank on par with those of a Floor Master. Proof of it is the fact that he never lost a single match except the two against Hisoka, who allowed him to survive because he had taken interest in his potential after Kastro scored the most points against him of any of his opponents.[1] His fighting style combines his advanced hand-to-hand techniques with the deception granted by his clone.[2] Kastro is also very adept at reading the flow of aura, even when it is not being released, as was the case when he exposed Killua's lie about not being interested in fighting just by looking at him.[1]

Preternatural Perception: Kastro managed to detect Killua's presence on his floor and its sudden disappearance, whereas the boy failed to do the same. He claims that this is normal for a fighter of his caliber.[1]

Enhanced Strength: Kastro is fairly strong, enough to mutilate a fellow Heaven's Arena fighter using only his bare hands.[2] He also managed to momentarily stun Hisoka with a sudden blow.[1][2]

Enhanced Speed: Although most of the attacks he lands are due to his disorienting the opponent with his Double, this strategy requires a great timing and a considerable amount of speed to work, since the target must not be permitted to see two of Kastro at once lest his ability is figured out.[2] In his confrontation against Hisoka, he managed to move behind the magician, and in his first appearance, he appeared behind Killua without the assassin noticing him approach, probably in conjunction with Zetsu or In.[1]

Proficient Hand to Hand Combatant: With the full degree of his abilities in this field being unclear, Kastro is still capable of performing the Tiger Bite Fist, an advanced technique that, as Killua stated, has enough power to cut down a tree if used by a master.[1] The martial art he employs appears to focus primarily on striking the opponent with one's hands, especially with chops and palm strikes. Kastro's swings are generally very wide, making them stronger but allowing skilled opponents to predict them, although this backlash is covered by his Double.[1][2][3]


Kastro is an Enhancer, but he also has considerable skills in the Manipulation and Conjuration types.[4] However, focusing on the latter two category at the expense of his natural one led to what Hisoka terms "Memory Overload", which stunted his progress.[3] Outside of Hatsu, Kastro seems to be capable of using Ko,[2][3] which requires knowledge of Ten, Ren, Gyo, Zetsu, and Hatsu.[5] He appears to be proficient in either Zetsu or In, concealing his presence so Killua failed to sense him.[1]

Kastro's Nen Type: Enhancement
Type: Enhancement[4] Tiger Bite Fist (()(こう)(けん)()()()()()()(), Kokōken)
Tiger bite fist 2011 Kastro enhances the strength of his hands, places them imitating the claws and fangs of a tiger and attacks the enemy with incredible strength. This attack is so strong that it is able to mutilate the enemy effortlessly.[2] Wing states that if Kastro spent more time mastering this technique instead of Doppleganger, he would have been one of the strongest Nen users alive.[4]
Type: Conjuration and Manipulation[4] Double (分身(ダブル) Doppelganger)
Doppleganger 2011 Kastro creates a double of himself that can attack and confuse the enemy, generally sending it against the enemy first while he moves in a favorable position. He is very adept at summoning and dispelling it so quickly that even an opponent of Hisoka's caliber had a hard time figuring out the nature of the ability. A giveaway is the fact that when the clone appears, Kastro's presence seems to double.[2] If the secret of his technique is puzzle dout, Kastro can simply fight in tandem with it. Despite its power, however, the ability has some flaws, including the immense amount of focus it requires and Kastro's inability to replicate the effects of a battle, such as dust and blood, on his clone, making the deceptive and trickery aspect of the ability inefective in a drawn-out clash.[3] Furthermore, the intense training Kastro, as an Enhancer, had to undergo to create the ability caused him to neglect his natural Nen category, Enhancement, where his true strength lies.[4]
Type: Conjuration, Enhancement, and Manipulation[4] True Tiger Bite Fist (()(こう)(しん)(けん)()()()()()(), Kokōshinken)
True tiger bite fist 2011 Kastro executes Tiger Bite Fist at the same time as his Double in a deadly tandem attack.[2]


  • Heaven's Arena arc
    • Kastro vs. Heaven's Arena fighters below the 200th floor (Past)[1]
    • Kastro vs. Hisoka Morow (Past)[1]
    • Kastro vs. Heaven's Arena 200th floor fighter (Past)[1]
    • Kastro vs. Heaven's Arena 200th floor fighter (Past)[1]
    • Kastro vs. Heaven's Arena 200th floor fighter (Past)[1]
    • Kastro vs. Heaven's Arena 200th floor fighter (Past)[1]
    • Kastro vs. Heaven's Arena 200th floor fighter (Past)[1]
    • Kastro vs. Heaven's Arena 200th floor fighter (Past)[1]
    • Kastro vs. Heaven's Arena 200th floor fighter (Past)[1]
    • Kastro vs. Heaven's Arena 200th floor fighter (Past)[1]
    • Kastro vs. Heaven's Arena 200th floor fighter (Past)[1]
    • Kastro vs. Hisoka Morow[1][2][3][6]


  • (To an interviewer) "I wouldn't fight if I thought I didn't have a chance. I'll prove that I'm a new man compared to two years ago."[1]
  • (To Killua) "I'll be waiting at Battle Olympia. I'm sure you can make it."[1]
  • (To Hisoka) "I'm grateful, Hisoka. Without your Initiation, I never would've gotten this strong."[1]
  • (To Hisoka) "You still won't change your mind? Will you die without figuring anything out?"[2]
  • (To Hisoka) "If you want to remain pompous, go ahead. I guess you weren't meant for anything more."[2]


  • Most of Kastro's battle with Hisoka was omitted in Nippon Animation's anime adaptation.

Translations around the WorldEdit

Language Name
The Arab world Flag Arabic كاسترو


  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 1.21 1.22 1.23 1.24 1.25 1.26 Hunter × Hunter - Volume 6, Chapter 52
  2. 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 Hunter × Hunter - Volume 6, Chapter 53
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Hunter × Hunter - Volume 6, Chapter 54
  4. 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Hunter × Hunter - Volume 7, Chapter 60
  5. Hunter × Hunter - Volume 15, Chapter 141
  6. Hunter × Hunter - Volume 7, Chapter 55