Twelve Guardians

The Twelve Guardians (十二天将) are the exorcists who inherited the names and powers of Abe no Seimei's shikigami. They are the most powerful exorcists behind the Chief Exorcist and Miko. Each are a member of a house descended from the twelve allies of Abe No Seimei in ancient times.

Strength, Powers and Abilities
The Twelve Guardians are the strongest rank of exorcists.

According to Narumi Ioroi's personal opinion, after assessing the Twelve Guardians members level of power, they would rank as following:
 * 1) Tenma Unomiya
 * 2) Tatara
 * 3) Seigen Amawaka
 * 4) Kankuro Mitosaka
 * 5) Shimon Ikaruga
 * 6) Subaru Mitejima
 * 7) Cordelia Kasukami
 * 8) Sakura Sada
 * 9) Narumi Ioroi
 * 10) Kengo Ujii
 * 11) Arata Inanaki
 * 12) Miku Zeze

In the anime, a Guardian is as strong as 1,000 Exorcists or more. It is determined that all of the Twelve Guardians are as strong as Abe no Seimei and Kuzunoha. They also able to perform special rituals called "Rikujin Shinka" and "Heavenly Blue Earth Ritual."

Succession
Some of the shikigami of the Guardians are pretty versatile at choosing successors, like Suzaku and Byakko, they simply choose at their will, among the members blood related to the house. Other houses such as the Mitosaka house would choose their Guardian on whoever possesses the Impurity Eater.

But in some houses succession of the Guardians are cruel. Like the Kijin Guardian, who is chosen among the survivor of ten candidates trying to kill each other, or Rikugō Guardians who must pass away to let the heir succeed, and the heir would carry all the power of deceased Rikugō Guardians, thus weakening the current Guardian's life energy.

Flight
It is said that only Suzaku's users are the only ones to have technique that enables flight. Later Keiji and Rokuro managed to use their enchantments as thrust to break that rule.

In anime, there are also Miku Zeze as Daion when she possesses her Giant Doll and Tenma Unomiya as Kijin when he is using his Sword as Hoverboard.

Mystic Spell Equip
All twelve members possess an enchantment known as Mystic Spell Equip (纏神呪 Matoi Kajiri) which amplifies the powers of the exorcists tenfold. The appearance of each enchantment vary from guardian to guardian, but generally change their overall appearances apart from specifically enchanted items such as swords, hammers, or gauntlets.

It has been mentioned that the use of the Mystic Spell Equip drains much of a guardian's spiritual energy, weakening them after the use of such a spell. Also, the duration of the enchantment is dependent on the overall power of the guardian; like with Mayura whose enchantment does not last long compared to the others prior to the timeskip.

Trivia

 * In the anime, Shimon is the first shown member of the Twelve Guardians; while in the manga, it was Seigen who was first shown. Despite this, Seigen's first appearance in the anime is similar to how he first appears in the manga.
 * The first and third kanji of the Twelve Guardians' enchantments are the same kanji that hold their own titles (e.g. 白蓮虎砲, Byakuren Kohō; the first and third characters also make up the name 白虎, Byakko).
 * There are 4 guardians who have yet to be seen in their Mystic Spell Equip forms in the manga; Arata, Subaru and Tatara.
 * Tatara's Mystic Spell Equip however is present in the anime.