Klein is the in-game name of Ryoutarou Tsuboi, a supporting character in Sword Art Online the Movie: Ordinal Scale. In the virtual world, he is the leader of the guild Furinkazan and favors Japanese-style weapons and armor, typically wielding a katana. His background includes surviving the death game of Sword Art Online, where he fought on the front lines and kept his entire guild alive throughout the ordeal. In the movie, Klein continues to play augmented reality games with his guildmates, wearing matching uniforms that display their strong group identity even in the real world. Personality-wise, he is known for being friendly, approachable, and quick-witted, often lifting the mood of those around him. He is loyal to his friends, especially Kirito, and is always ready to lend a helping hand without holding grudges. His motivations center on supporting his comrades and enjoying the game experience together. In the story of Ordinal Scale, Klein is an early participant in the new AR game and joins Kirito and Asuna in a boss fight at Akihabara. Later, he and his entire guild are ambushed and physically defeated by the antagonist Eiji, resulting in Klein being hospitalized with a broken arm and losing some of his SAO memories as a consequence of the memory-harvesting scheme. Despite this setback, he recovers and ultimately joins the final battle in full-dive mode when Yui restores the players’ SAO abilities, fighting alongside his friends to stop the plot and save the other survivors. His key relationships include his close friendship with Kirito, which dates back to the first day of the death game, and his bond with his Furinkazan guild members, whom he leads with dedication. Over the course of the film, Klein demonstrates resilience and unwavering camaraderie, showing that even after being injured and losing part of his past, he remains a reliable ally. His notable abilities include skilled swordsmanship with a Japanese-style blade, effective leadership in group combat, and the adaptability to transition from full-dive to augmented reality gameplay.