The oldest of the Numbers, has been Scaglietti's accomplice in many incidents. Her IS (Inherent Skill) allows her to obtain and process data without making use of conventional means, hence being undetectable. She also received mental implants to optimize her intel management and general mental reflexes. In a battle her role is similar to that of an AWACS unit, taking charge of the communication between units and data gathering.

She is the first Number ever to be created and Scaglietti's personal secretary. With a calm and collected personality, acting for Scaglietti's benefit is always her utmost priority. Uno is greatly respected by her sisters due to her seniority and none of them will disobey a direct order from her. She is the one who understand Scaglietti the most and will always support him in both actions and thoughts.

-Wikipedia-