He has messy, short, curly brown hair, big brown eyes and thick eyebrows. Twelve is a slim young man with a somewhat effeminate appearance. It is also hinted that he has an enhanced sense of smell in Episode 1, where he immediately smells chlorine from a distance and in Episode 5, where he smells fire before Nine does. His memorization skills are also implied in this same episode when Nine asks Twelve whether he had remembered their plan and Twelve questions the necessity of the confirmation. This ability was also portrayed in episode 1 when Twelve memorizes many of the names of the students from the school that they attended in a short period of time. This scene also shows that he has an exceptional memory as he was able to memorize where each security camera was located. It was shown that he was intelligent when it came to escaping security and other types of guards, as shown in episode 7. He was an apt motorcyclist and handled vehicles easily on multiple occasions, he used this skill to escape police pursuit. Nonetheless, he was loyal and dependable, had a keen sense of social intuition, was on brother-like terms with Nine, and had performed numerous empathetic acts towards Lisa Mishima.

However, he was able and willing to adopt ruthless and violent methods if the situation called for it, and it was safe to assume that he had taken significant psychological damage from his time in the aforementioned children's institution. On the outside, he was a typical jokester: light-humored and energetic, enjoying messing around with other people's business.

Zankyou no terror twelve