Gogo Yubari is a seventeen-year old schoolgirl who is lethally skilled with a Chinese martial weapon, similar to a Meteor hammer aka a Manriki (and referred to in the action figure release as a morning star). She is Ishii's chief bodyguard and an assassin. A violent psychopath, she kills for fun and derives great pleasure in inflicting pain; it was said that what Yubari "lacks in age, she makes up for in madness." A cut-away shows Yubari drinking at a bar and being propositioned by a rather ugly and presumably perverted older businessman. When Gogo asks if he wants to screw her and he responds in the affirmative, she stabs him with a concealed dagger, proudly proclaiming, "How 'bout now, big boy? Do you still wish to penetrate me? Or is it I...who has penetrated you?"

When Beatrix Kiddo enters the House of Blue Leaves to exact her revenge on Ishii, loyal Yubari is the seventh bodyguard to take her on. Before their clash, Kiddo tries to persuade Yubari to desert Ishii, but she refuses. A tense battle ensues, with Yubari having the upper hand throughout much of the fight. Just as she manages to wrap the chain of her weapon around Kiddo's neck, however, Kiddo grabs a smashed table leg with nails protruding from it and drives it spikes first into Yubari's foot. The pain causes Gogo to releases her grip on the chain around Kiddo's neck, allowing her to drive the table leg into Gogo's head, killing her almost instantly.