He is one of the three Heavens Arena fighters who wanted to challenge Gon and Killua for easy wins. He appears to be mean and will do everything in order to become a Floor Master. In the past, he has reached the 200th floor as a rookie without the use of Nen, later was "initiated" after being attacked with a malicious aura attack and lost his left arm. One of Sadaso's dirty tricks was to kidnap Zushi with his Nen hand to threaten Gon to join a match with him. However, Killua learns of the fight between the two and makes a threat against Sadaso's life, frightening him enough to leave Heavens Arena for good. It still remains unknown whether if Sadaso wears a mask or not, which is commented by a ticket seller when he was talking to Killua. When he leaves Heaven's Arena after Killua's threat, he is wearing sunglasses for the first time and his face looks less pale than before. At this point, when he is leaving Heavens Arena, he calls Gido to warn them that Killua will come after them next.
Zeno Zoldyck (ゼノ�ゾルディック Zeno Zorudikku) is Killua's grandfather and Silva's father. A witty old man, his advancing age has not dampened his quick thinking and speed in battle. Zeno wears alternating signs on his garb that say either "A Kill A Day" or "Never Retire." He appears to be on good terms with the Hunter Committee's Chairman, Netero, who hired Zeno to assault Ming Jol-ik's palace in East Gorteau in order to catch the chimera ant King off guard. Zeno favors Killua more than his other grandchildren, most likely because Killua is the heir of the family. Source: HunterXHunter.wikia
Silva is Killua's father. A silent, pensive figure, Killua's interaction with him seems not to be much. He allows Killua to go along with Gon on their journey, but this is only so Killua will gain more experience when thrown out into the real world on his own. During the September third portion of the York Shin City arc, Silva and his father Zeno are both hired by the Mafia to assassinate the Genei Ryodan, but withdraw from the job when their clients are murdered by Illumi, Maha, and Karuto.
Menchi was one of the two judges that presided over the second stage of the Exam. Her exam topic was to prepare a piece of sushi for her to taste. If it meets up to her stringent expectations the candidate would pass.
Hanzo is an 18-year old Jounin ninja from the Cloud Hidden Village whom has trained in the art of ninjutsu from the moment he could stand. He decided to become a Hunter in order to find the elusive Hermit's Scroll. After the first part of the exam, which is a marathon, Hanzo is easily able to converse while running--most of the others are breathless and struggling. In the second test, featuring cooking, he is the only one to know what 'sushi' is. He is the third candidate to clear the deadly traps and puzzles of the Trick Tower. When several people are stranded in Lippo's 'bonus stage', Hanzo takes the lead in getting them out. In the final test of the Hunter Exam, Hanzo is forced to battle Gon. His speed, strength, and battle experience easily exceed that of Gon. However, the only way to pass the final test to is force your opponent to admit defeat--Gon refuses to do so even after being severely beaten. Hanzo breaks Gon's arm to force him to admit defeat, but Gon still refuses. Noting the lack of hate in Gon's eyes after this act, Hanzo realizes he actually has come to like Gon. He willingly bows out of the battle, giving Gon the victory needed for him to pass the final test. Hanzo was examinee #294 during the 287th Hunter Exam. It is later stated by Wing that Hanzo learned Nen after the Hunter Exam. He later reappears in manga chapter #350, apart of Kurapika's group (Included in the group are Basho, Izunabi, Melody and Biscuit). (Source: Wikipedia)
Examinee #16 during the Hunter exam. Tompa is nicknamed the "Rookie Crusher" by other candidates with more experience taking the exam. Tompa has taken the exam for 35 consecutive terms (given that the Hunter exam can only be taken by someone who is at least 12, it means that Tompa either was lying, sneaked in the first two times, or that the age limit is a new rule), but has somehow never managed to pass. He often brags of his experience to those taking the Hunter Exam for the first time and then offers them a helping hand. Of course, this is merely subterfuge as he takes a perverse pleasure in sabotaging their attempts to get the license.
Dalzollene is a leader of Neon Nostrade's bodyguards and Kurapika's direct superior. His weapon is a katana inscribed with runes that increase its power when infused Nen. In the anime, he manages to pierce Uvogin by 5 millimeters with the katana. He appears to enjoy music and is dedicated to his job. He also was not hesitant to sacrifice three of Neon's bodyguards when she predicted Troupe activity at the Yorknew Underground Auction. He had developed his Ten so that he could defend himself from ten bullets. He is later killed by Phinks, as the Phantom Troupe infiltrate a Nostrade compound in order to rescue a captured Uvogin. (Source: Wikipedia)