Rudbornn is the leader of the Exequias, a group responsible for dealing with rebels and intruders in Las Noches. Unlike most arrancar, his face is hidden. He carries a zanpakutō, but its name and released state have not been revealed. He and his subordinates clean up after each battle, collecting data for Szayel Aporro Grantz before killing any survivors: they kill two of the three Privaron Espada off screen for failing to beat their opponents, and prepare to do the same with the third before being stopped by Retsu Unohana. Surprised by the arrival of a Soul Reaper captain, Rudbornn and the rest of the Exequias withdraw in order to avoid conflict. Later he and the rest of the Exequias attempt to bar the progress of Ichigo, but they are intercepted by attacks from Ichigo’s comrades.

(Source: Wikipedia)
Source: Bleach official character books III