The Nabuu Brothers are a pair of identical twin men from an African shamanistic background, belonging to the San people. They serve as supporting agents within the government's Supernatural Disaster Countermeasures Division, working alongside characters such as Yomi Isayama and Kagura Tsuchimiya. Their shared name stems from a cultural tradition in which twins are given the same name, and their identical appearance often leads to confusion among teammates about which brother is older and which is younger. In conversation, the two frequently complete each other's sentences, reinforcing their close bond and synchronized manner. As members of the division, their motivation is to carry out their duties in combating supernatural threats.

Their role in the story is that of capable field operatives, though they remain minor characters. During the events of Ga-Rei: Zero, one of the brothers is killed in battle against the antagonist Ranguren. The surviving brother later dies while attempting to rescue Fujiko Mine during an attack by the Juugondou organization on the Ministry. In the original manga, only a single Nabuu appears as a minor, non-speaking character, reflecting the loss of his twin in the anime prequel. No specific supernatural abilities beyond their status as shamans are detailed, and their personal development is limited due to their peripheral involvement and early deaths. Their key relationships are with their fellow agency members, with whom they cooperate loyally until their demise.