"Aiji Ishibashi" is a false name. It is unknown what his real name is.
Aiji has black hair and black eyes. Though he is Japanese, his younger brother Yellow is Caucasian. The two have identical facial features. There is a sharpness to his gaze.
Aiji is an honorable and polite man, and is much calmer than his hot-headed brother. He is not entirely stoic and serious (as his appearance and demeanor might imply) - he has a good sense of humor, and is very fond of puns.
He seems to value the lives of strangers more than his brother does.
He is prone to frequently arguing with his brother. Despite their clashes, they both have a mutual respect for Gerhardt von Waldstein (who rescued them when they were children).
(To be added)
He wields a bamboo shinai sword.
He can manipulate shadows. His shadows are indigo-colored, and he can use shadows to travel between locations. He can solidify his shadows, and use them physically on others.
Aiji has a wide range of other abilities, including turning his body into acid.
- He likes california rolls, and puns.
- He calls his Shadow Manipulation ability Ninpō: Shadow Play but is too embarrassed to say it out loud.
- His chosen first name Aiji means 'indigo child', and his chosen family name Ishibashi translates to "stone bridge" - so, he and Yellow essentially decided to share the same surname with their aliases.