Nonette Enneagram

Autism is a neurodevelopmental disorder characterized by impaired social interaction, impaired verbal and non-verbal communication, and restricted and repetitive behavior. Parents usually notice signs in the first two years of their child's life.[6] These signs often develop gradually, though some children with autism reach their developmental milestones at a normal pace and then regress.[7] The diagnostic criteria require that symptoms become apparent in early childhood, typically before age three.[8]

Character Outline
Nonette is a carefree person and has a frank personality. She attended military school with Second Princess Cornelia, who considers Nonette her senior. An upbeat and cheerful woman, she is one of the few people Cornelia actually fears. Her first and last names contain the Latin and Greek prefixes for 9, non- and ennea- respectively. Her last name may also be a reference to the Enneagram of Personality. She first appears in the PSP/PS2 video game, Code Geass: Lost Colors and serve as some sort of mentor or older sister figure to the protagonist if the player decide to choose the Britannian Military route, she is also always seen carrying a pistol with her. It is never shown whether she had ever actually used it, but given her military background, she must have had some proficiency with it. Out of all the Knights of the Round, she is the only one who has no speaking role in the anime. However, she appears as a major supporting character in the second half of Oz the Reflection.

In Oz the Reflection, it is mentioned that she is old friends with Kanon.

Second Season
She is briefly seen when all the Knights of the Rounds make their first appearance together watching Zero broadcasting his plan to recreate the United States of Japan. She is later seen, along with Gino and Bismarck, watching the broadcast of Lelouch making his ascension to the throne along with Suzaku. It is unknown what happened to Nonette following Lelouch's ascension to the throne, as she does not reappear and is not referenced to either.

Oz the Reflection
Nonette arrives in Area 24 after the Great Glinda Knights' battle against the Star of Madrid. At the request of Kanon, she is to observe Marrybell.