The Royal Guard of the Spirit King, tasked with his protection and the defence of the entire Soul King Palace.
The Royal Guard, otherwise known as the Zero Division, are the strongest fighting force under the direct command of the Spirit King himself. Their main purpose is the protection of the Soul King Palace, along with the King and his family, however it was also mentioned that they are also responsible for the slaying of Menos class Hollows. The Royal Guard seemingly have a small defensive force at their command in times of great emergency, however the nature of these soldiers has yet to be revealed. The proper process for the selection and promotion of a Shinigami to the Royal Guard is largely unknown, but we know that to become a Royal Guard member, one must make a significant contribution to the Soul Society in the Kings eyes to be deemed strong enough to be inducted into their illustrious ranks. The power of the Royal Guard is also legendary, as despite the fact it only has 5 members in its ranks, the overall power of the Royal Guard is deemed greater than the entirety of the Gotei 13.
All members of the Royal Guard are gifted an entire city of their own when they arrive in the Soul King Palace. Each city floats in the air around the Greater Soul King Palace, and each city is tailored for the Captain whom it belongs to. These cities can seemingly be populated by the Captains through unknown methods, and each city serves as a personal palace hub for the Captains to do whatever they wish.
When venturing down into the Soul Society, the Royal Guard utilize the Tenchuren, a massive pillar which drops from the Soul King Palace, through the 72 barriers protecting it and down into the heart of the Soul Society. They have also shown the ability to create a set of spiral stairs down to the Soul Society, however the journey is deemed to be incredibly long, even when utilizing Shunpo.
|Ichibei Hyosube||Otherwise know as "The Monk Who Calls the Real Name", Ichibei is the de-facto leader of the Royal Guard and one of its most powerful members. The reason for his induction is due to the fact that he is able to see the "true name" of anything, and in doing so named all things currently in the Soul Society.|
|Kirio Hikifune||Otherwise known as "Ruler of Grain", Kirio is a powerful member of the Royal Guard who speciliazes in advanced cooking which can increase the strength and power of any who eat it. The reason for her induction was due to the fact that she created the Artifical Soul.|
|Oh-Etsu Nimaiya||Otherwise known as "God of the Sword", Oh-Etsu is a powerful member of the Royal Guard who manages the creation, distribution, and upkeep of Asauchi and Zanpakuto. The reason for his induction was due to the fact that he created the Zanpakuto.|
|Senjumaru Shutara||Otherwise known as "Great Weave Guard", Senjumaru is a powerful member of the Royal Guard who is seemingly in charge of creating Oken infused clothing and the general upkeep and security of the Soul King Palace. The reason for her induction is currently unknown.|
|Tenjirou Kirinji||Otherwise known as "Hot Spring Demon", Tenjirou is a powerful member of the Royal Guard who is incharge of maintaining the Healing Springs in the Soul King Palace. The reason for his induction was due to the fact that he created the Healing Hot Springs.|