Royal Guard

The, also known as the Zero Division (Squad Zero in the English dub), 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, excluding former Lieutenant of the 8th Division, Vizard Lisa Yadomaru. They are said to have considerable power and tactical knowledge. The Royal Guard are expert Shinigami that were promoted to protect the Spirit King.

Members
All members of the Royal Guard are former Captains of the Gotei 13. Only one has ever been mentioned in the series: who was the Captain of the Twelfth Division.

Trivia

 * Despite the current war being used by Aizen to create a key to become Spirit King, the Zero Division has yet to make an apperance.