Hunter × Hunter - Season 1 Episode 30

Satotz explains to Gon that Killua failed the final stage. His opponent turns out to be his older brother Illumi in disguise. Illumi questions Killua and determines him unfit to be a normal person. He believes that Killua has a talent to be an assassin and tells him to return home. Illumi threatens to kill Gon if Killua even attempts to fight him, so Killua gives up and becomes silent for the rest of the exam. Killua murders Bodoro in the middle of his match with Leorio for no reason and is disqualified. Having heard this, Gon confronts Illumi and breaks his arm, deciding to go look for Killua.