While Fujiko is not part of Lupin's gang, she often participates in their exploits either as a partner or a competitor. Her principle tactic is to stick with Lupin and company until the plunder is made available then double-cross her colleagues. Frequently, she finds it necessary to betray Lupin to get close to the enemy, then after ingratiating herself into his trust will acquire the swag and escape (rarely, she will help to extricate Lupin, Goemon and Jigen for the trouble she put them into, as if to atone). Fujiko is also known to provide Zenigata or other law enforcement officers with information and assistance in order to gain her own freedom . At one point, Fujiko was made Zenigata's replacement on the ICPO's Lupin operation, however this was a cover for her to get into a secret vault.

Of this two-faced nature Lupin is surprisingly forgiving. In the 1995 movie Die! Nostradamus, Lupin carefully treats the amnesiatic Fujiko, hoping she gets better as he "looks forward to her betrayals".