Royal Guard

The, also known as the Zero Division (Squad Zero in English), it is made up of former Captains of the Gotei 13 who have been promoted to this level. Only captains of the Gotei 13 know of their existence. They are said to have considerable power and tactical knowledge. The Royal Guard are expert Shinigami that were promoted to protect the King. They are the highest class of Shinigami and only answer to the King, not even the Central 46 has authority over them. It is also known that they are meant to hunt Menos(Episode 14). This has been disproved by normal,and/or unseated, and/or non-Royal Guard Shinigami dispatching Menos with ease. It is possible that this is a mistake or continuity error, possibly due to unresolved story ideas.

Members
All members of the Royal Guard are former Captains of the Gotei 13. Only one has ever been mentioned in the series, that being who was the former Captain of the 12th Division.