Nine
Known as Nine, is one of two members of the Sphinx terrorist group. He grew up in an experimental institution for gifted children with Twelve, though the both of them managed to escape. Later on, both Nine and Twelve carry out several terroristic acts in Japan.
He is reserved, calm and collected, and very, very intelligent. Nine is efficient in many fields, up to exceptional computing and hacking. He’s an impeccable strategist, with a knack for chess and classical literature. Good with disguises.
Nine is strongly implied to have been killed by the American government in the last episode of the series, although his death is not seen. One year later, Lisa is seen visiting the graves of the institution children, two of which are marked with a 9 and 12. She also runs into Shibazaki, who asks her if she was done visiting their grave.