The six major occupational magic [Warrior], [Clergy], [Mage], [Blacksmith], [Searcher] and [Scholar].
There was a great sage who captured all of them through repeated reincarnations and became the strongest in the world in each of their occupational magic.
However, he realized that there was a limit to his strength in one occupational magic in one life, and he despaired.
The sage almost gives up, but realizes that the only inferior occupation [villager] that was thought to be unable to use magic is actually an all-powerful occupation, and is reborn.
The Great Sage is reborn as a villager and silences the people who mocked him for being an inferior person, and becomes the strongest in the world.