Kastro

Kastro (カストロ, Kasutoro) was a prominent fighter in the Heavens Arena and an apparent celebrity. He lived on the 200th floor of Heavens Arena, with the intent of accumulating enough wins to become a Floor Master. His only appearance is the lead up to his rematch with Hisoka.

Background
Two years prior to the start of the series, Kastro fought Hisoka in the Heavens Arena. He scored a knockdown and won three points, but was ultimately defeated. After this, he trained rigorously to improve his Nen, and gains nine wins. He then challenges Hisoka for his tenth win, confident he could defeat him. Kastro kept his Doppelganger ability hidden.

Heavens Arena arc


Kastro is first mentioned when his rematch with Hisoka reaches Gon's and Killua's ears. He uses his "Doppelganger" ability to confuse Killua when he approaches the fighter for an autograph. Kastro easily foresaw Killua's arrival, noting how his aura disappeared when he used Zetsu upon entering the floor.

When his match with Hisoka begins, Kastro quickly lands the first three hits, using his "Doppelganger" ability to catch Hisoka by surprise. He is awarded a clean hit and knockdown by the referee, gaining a 4-0 lead over Hisoka.

After Hisoka's first explanation of his "Doppelganger" ability, Kastro deems it futile to attempt to understand his ability if Hisoka continues running in circles. He then says he'll take Hisoka's arm with his next attack, because he is done waiting. Kastro becomes displeased with Hisoka's lack of enthusiasm or reaction to his threat and decides to use his "Tiger Bite Fist". Hisoka catches him off guard by offering his left arm. Kastro sees it as a bluff and instead takes Hisoka's right arm off, exclaiming that he can't take control that easily.

Hisoka then understands Kastro's "Doppelganger" ability, which impresses Kastro. They engage in brief conversation before Kastro begins to use his "True Tiger Bite Fist", threatening to take Hisoka's other arm with the attack. Kastro's undoing was in the type of Hatsu ability that he had chosen. Although he was born an Enhancer, Kastro's "Doppelganger" ability completely ignored his strengths and used Conjuration and Manipulation abilities. An Enhancer's maximum ability in these fields is 60% at best, so for Kastro is difficult to use and requires a lot of nen and concentration.



Despite this, Kastro combines his two abilities to cover the defects of his double, making a lethal combination, but Hisoka takes advantage of Kastro's weaknesses, distracts him with his abilities and ultimately kills him.

Abilities & Powers
Kastro demonstrated himself to be a very skilled fighter with considerable physical combat skills that excels in hand-to-hand combat. He has an extremely sharp mind, able to stay calm in most situations. He is slower than Hisoka, but faster than Killua.

Trivia

 * His battle with Hisoka was mostly omitted in Nippon Animation's anime adaptation.