Episode 1
On the ship bound for the Hunter Exam, Leorio is introduced as a seemingly shallow older applicant, lounging against the rail with a dirty magazine while other candidates mock Gon’s big declaration about becoming the best Hunter in the world. He immediately comes off as loud and blunt, scoffing at both Gon and the situation around him.
During the stormy voyage, Leorio proves tougher than most applicants. While nearly everyone else is incapacitated by seasickness and violent waves, he’s still conscious—first seen chomping into an apple (and complaining that it’s sour) while the captain quietly notes that there are a few “tough nuts” aboard, grouping Leorio with Gon and Kurapika. Later, when Gon is summoned to the bridge with Kurapika and Leorio, Leorio bristles at the captain’s questioning. He protests that if the old man isn’t an examiner, he has no right to “boss them around,” and he’s annoyed when Gon openly answers. Leorio insists he doesn’t want to reveal why he’s taking the exam and labels Gon “not a team player” for being so straightforward.
As Kurapika explains his tragic past and desire for revenge against the Phantom Troupe, Leorio acts as both skeptic and provoker. He bluntly reduces Kurapika’s motivation to simple revenge and questions whether becoming a Hunter is really necessary for that, earning Kurapika’s contempt and being called stupid. This triggers Leorio’s pride: he repeatedly demands to be addressed as “Leorio-san,” fumes at Kurapika’s insults, and finally snaps when Kurapika mocks his intelligence. When Gon asks Leorio why he wants to be a Hunter, Leorio answers without shame: he wants money—a big house, a nice car, good liquor—and Kurapika counters that money can’t buy class. This escalates their conflict until Leorio storms toward the door, threatening to “end the filthy Kurta bloodline” and challenging Kurapika to settle things outside.
While Leorio and Kurapika face off on the rain-soaked deck, knives and wooden swords drawn, the storm and approaching waterspout turn their quarrel into a crisis. A powerful gust rips Katsuo into the air, sending him flying off the ship. Both Leorio and Kurapika immediately drop their fight to save him, lunging to grab Katsuo but only managing to clutch the ship’s edge. Gon dives past them to catch Katsuo, and Leorio and Kurapika grab Gon's legs to pull both boys back up, working together under pressure. After Katsuo is rescued and the ship escapes the waterspout, Leorio scolds Gon for his recklessness, insisting that without their help Gon would be “shark bait,” but Gon cheerfully points out that they did catch him, forcing Leorio to acknowledge their teamwork.
Once Katsuo regains consciousness, he thanks Gon for saving his life, and Gon redirects the credit to Leorio and Kurapika. Put on the spot, Leorio becomes awkward and embarrassed, rubbing his head and shyly admitting he’s glad Katsuo is okay. This sets the stage for reconciliation: Kurapika apologizes for his earlier rudeness and addresses him as “Leorio-san,” while Leorio, blushing, tells him just to call him “Leorio” and apologizes in return, retracting what he said about the Kurta. By the time the captain appears to announce that he likes them and will personally see them to the port nearest the exam site, Leorio is standing alongside Gon and Kurapika as part of a newly formed trio. He smiles when the captain declares that all three of them pass, and he’s present when Gon celebrates, marking Leorio’s shift from abrasive loner to grudging ally and eventual friend.