By all appearances, a healthy, normal teenage girl. In reality, she's living proof of what can be accomplished with state-of-the-art robotic technology and the brains of a cat. She has enhanced strength, speed, agility, and swims like a hammer. Her 'father' was a renegade scientist running from Mishima Heavy Industries, Kyuusaku Natsume, and she lived with him and his son Ryuunosuke. Her 'Mother' and Kyuusaku's enraged and currently seperated wife, Akiko, runs Mishima Heavy Industries, and isn't hesitant to send the latest in weapons technology to flatten her husband and get her son back. Nuku is very protective of her 'father' and 'brother', playful, somewhat simple-minded, and has an addiction for mouse chasing and eating fish.
Nuku-Nuku in 'Battle Mode' (and in her Waitress outfit too.)