Clerics of the Seven Luminaries

The Seven Celestial Sages are the most influential people in the Holy Kingdom Ruberion.

Background
The Holy Kingdom Ruberion's most influential officials. These beings are completely secluded and never appear in public and are only discussed as legends in fairy tales and other such stories. They typically train their successor personally, and no one knows when the successor takes over. In other words, the fact that they all trained one person is beyond unusual. At most, no more than six gather at the same time. Only the Seven Celestial Sages can directly meet with the emperor.

The Seven Celestial Sages are actually strong Humans who has received Ruminas's blessing and given a long lifespan in exchange for their services.

Chronology
Because they feared that the Priest Adalman would surpass their Sage status as a True Hero, they sent him to his death to face a Zombie Dragon.

They also tried to pit Hinata Sakaguchi against Demon Lord Rimuru Tempest.

They were killed after their plot to eradicate both Hinata and Rimuru was revealed. (Light Novel)

Abilities
It is said that each has transcended a hero-class existence and is a legendary being that is often in charge of rearing new heroes.