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)