A shinobi fascinated by order and beauty, and the lover of Mugen who assists him in the freeing of Takuma. A Sugar-and-Ice Personality individual who can blend in with crowds using disguises.

Her color is purple, reflecting her calm, orderly personality. Aiko is good at disruption: using her sneeze powder to limit guard viewcones allows her and her allies to slip by at near point-blank range, and if she is disguised then she can keep a guards attention—even Straw Hats—fixed on her perpetually. Both of these skills allow her to poke holes in guard patrol routes that the others can dutifully exploit. Samurai see right through her disguises however, and while the ability to distract guards is useful, she needs to take it off to perform actions like climbing, swimming or even crouching, and it takes a while to change into her disguise.