Nero the Sable "Nero the Jet-black Darkness" is a member of the Tsviets and Weiss's younger brother. Nero has black hair, masks nearly all of his face, and has a set of mechanical wings. He has the power to control darkness, as he had been injected by stagnant mako when he was still a fetus. Nero is voiced by Ryotaro Okiayu in Japanese and Mike Rock in English.
Nero first appears in Dirge of Cerberus, using his power to engulf others. Throughout the game, Nero protects Weiss and keeps others from disturbing his resurrection. When Vincent arrives at Weiss's chambers, Nero transports himself and Vincent to another dimension. Upon his defeat, Nero returns to the chambers and Weiss awakens, fully reborn. However, Weiss has been taken over by the scientist Hojo, and immediately impales Nero after awakening, noting he no longer has any use for him. Nero, who had been injected with stagnant mako, transferred himself into Weiss's body, infecting Weiss's "pure" body and freeing him from Hojo. Nero has a brief appearance with Weiss in Crisis Core, wherein he and Weiss carry the unconscious Genesis to a helicopter.