Arbitrator

Arbitrators are mages with unique abilities, and each one possess their own attribute. All of them possess high class magic close to a Paladin, some are Paladin class. Paladins call this place their home. Respectively, It consists of pillars that each member stand on. Unlike the Trinity Seven, they don't possess a Grimoirs, they don't have a Thema's nor an Archive to connect to, as they can use their powers and abilities freely, however if they get serious they can use Their respective Thema and Archive. According to Master Bibilia if one Arbitrator is missing, they can be replaced by another one, though they must meet the requirements of the missing one.

Origin
The place the Arbitrators in is in another world isolated from the real world, but it's not an island. Only the Arbitrators themselves know where it's located, as well only them themselves can enter and leave the place, however if they wish so they can bring others only if the situation is dire. An Arbitrator can retire if they wish so as well.

Requirements
To become an Arbitrator, the mage must have incredible magic power inside them. They must achieve their own representatives as well as attribute via their own will or by extensive training.

Paladin class mages can become one easily, hence their massive magic power, yet becoming one isn't very easy but their process is much faster than normal mages. Some Paladins can become an Arbitrator without doing anything or training if accepted. Famous Paladin such as Master Bibila and Master Liber are qualified as an Arbitrator.

To achieve the rank of an Arbitrator is also completely rare, since they can use abilities according to their attribute willingly, without the use of any kind of Grimoires, however they do have a unique Thema's that an Arbitrator use from what they "represent" and they connect it to their corresponding "attribute" instead of Archive.

A Trinity Seven is capable of becoming an Arbitrator, though they must perfect their own abilities to the limit, as well the chance is very rare and nearly impossible, but they can be chosen as a substitute if their is a missing Arbitrator or if one wishes to retire, even so the chance is still rare if not unacceptable.

Known Candidates:
Due to the Heavenly Arbitrator missing (which was Arles Azazel, whom she specialized in library studying) Master Bibilia had no choice but to bring the closest members of his school who are familiar with Arles line of work.
 * 1) Akio Fudo
 * 2) Selina Sherlock
 * 3) Mira Yamana

Although Akio doesn't count, as she was a substitute for Master Liber, since she wants to retire.

Trivia

 * Since Arbitrators have insane amount of magic power inside them, killing one is nearly impossible though they can only wound them badly enough as seen when Faunaria used a powerful thunder strike against Master Liber and Lugh.
 * Even so Arles Azazel never shown any of her powers as an Arbitrator, Maris revealed due to her knowledge she created a very dangerous and destructive technique.
 * The leader of the Arbitrators is Aetheria Akasha which is none other than Arsha's mother, she is also aware that her daughter trained Mira to be a better Hero Candidate.