Numbuh Three (real name Kuki Sanban) is one of the main five children from Codename: Kids Next Door and is the most childish in terms of personality. Her home nation is Japan (making her and Samurai Jack the only Japanese characters in FusionFall). She has two uptight parents and a younger sister in her family. Her biggest weakness is her love for every type of animal and her favorites are the Rainbow Monkeys, stuffed toy monkeys. As an adult, she later married Numbuh Four and became the president of the Rainbow Monkey Corporation.
FusionFallIn FusionFall, Numbuh Three is lost in The Future when Fuse's forces nearly conquer Earth. In the Past, she's at Mount Blackhead with Numbuh Four, Coco, Mac, and Ed. She wonders about Mandy's cold personality and thinks she needs a hug. Her sweet personality has easily made her friends with Bubbles, in which Numbuh 3 helps mend the injuries of Bubbles' squirrel, Bullet, during Squirrel Squad; she then directs the player to the local Infected Zone to investigate the culprit of the attack on Bullet. When the player heads for Monkey Mountain to complete the Numbuh Three Nano mission, she asks for the player's aid in saving a family of Rainbow Monkeys, including Baby Monkey, who was in the possession of Fusion Numbuh 3.
- She and Numbuh Five are the only ones from the KND whose Nano types aren't the same colors as their sweaters.
- In Numbuh Three's Nano mission, Numbuh Three tells the player to "Defeat Fusion Juniper Lee," when actually the player will be fighting Fusion Numbuh Three.