Kastro 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 and winning a rematch against Hisoka. Kastro was shown as being both a calm and reflective man, as he kindly greeted Killua, complimenting his Zetsu and his high aura. He was a very cautious man who takes his opponents seriously, as he kept tabs on all individuals on the 200th floor. Contrast to his seemingly composed demeanor was his ability to hold strong grudges towards those who had defeated him, as he became extremely 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 Heavens 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.
Hunter x Hunter
Hunter x Hunter is set in a world where Hunters exist to perform all manner of dangerous tasks like capturing criminals and bravely searching for lost treasures in uncharted territories. Twelve-year-old Gon Freecss is determined to become the best Hunter possible in hopes of finding his father, who was a Hunter himself and had long ago abandoned his young son. However, Gon soon realizes the path to achieving his goals is far more challenging than he could have ever imagined. Along the way to becoming an official Hunter, Gon befriends the lively doctor-in-training Leorio, vengeful Kurapika, and rebellious ex-assassin Killua. To attain their own goals and desires, together the four of them take the Hunter Exam, notorious for its low success rate and high probability of death. Throughout their journey, Gon and his friends embark on an adventure that puts them through many hardships and struggles. They will meet a plethora of monsters, creatures, and characters—all while learning what being a Hunter truly means.
