Two large twin brothers who both have the same name, as they come from a culture that give twins the same name. Both brothers tend to finish each other's sentences. Because they look identical, it leads some of their teammates to confusion. In the manga, only one of the Nabuu brothers appears (as a minor character with no lines) since the other brother was killed by Ranguren in Ga-Rei: Zero. The surviving Nabuu was later killed during the Juugondō's attack on the Agency, after trying to protect Fujiko Mine from enemy fire.
An omake in volume 5 of the manga states that the Nabuus are part of the San people from Africa, further confirmed in their character page on the anime's official website. According to the omake, they lost their home and family to war.