The pen is mightier than the sword.
The Sage (賢者, Kenja?) is a job class that has appeared in a number of games in the Final Fantasy series. The sage could be considered the ultimate Red Mage, being able to cast both Black and White Magic. However, the Sage is physically very weak with virtually no prowess with weapons. They also have low HP and speed and weak physical defenses as most mage-type classes do. Sometimes they have a lower MP total than a regular mage, but this is compensated by their ability to use any kind of magic from both schools unlike the regular Red Mage that has a limited pool.
The Sage job is granted to the party in Eureka in the original version, and by the Earth Crystal in the 3D version. The class is able to use Black Magic, White Magic, and Summon Magic all at once, essentially making them the strongest magic class in the game. However, in the 3D version they have limited MP to use them, random summoning instead of high summoning, and less Mind and Intelligence than the Devout and Magus, the strongest dedicated White and Black Magic jobs.
Tellah is a Sage and is able to cast limited White and Black Magic when he joins the party, as he has forgotten much of his spells in his old age. He later remembers the spells he has forgotten, giving him the ability to cast all but a select few spells. Fusoya is classified as a Lunarian, but also has the ability to use White and Black Magic, and can cast all the spells in the game (of course, this is because Lunarians created the concept of magic to begin with). Both Tellah and Fusoya have very low MP, however.
Nobody's going to call you a sage just because you've learned black and white magic. You have to throw away your own wishes and ambitions, Palom, and learn to use your magic to benefit the whole world...not just yourself.
The goal of becoming a Sage is central to Palom and Porom's Tales. Palom wishes to become a sage like Tellah and trains in various places around the world to hone his skills in Black Magic, but he shows no prowess in White Magic.
Leonora is officially classified as an Epopt, but is able to learn all White Magic and eventually most Black Magic. Palom suspects during his training her in Black Magic that she wishes to become a Sage, but she rejects this. During the ending, Leonora arrives at Mysidia to officially train to be a Sage.
Though the game does not have an official job system, Seymour Guado is able to use both White and Black Magic when he is a temporary party member, and has the ability to summon but cannot do so while being part of the party during the short time he is available. This makes him similar to a Sage, especially the Sage job from Final Fantasy III. As a temporary party member, Seymour's abilities in general are much stronger than the other party members'.
The Sage is a class exclusive to the nu mou. The Sage is able to use numerous status-inflicting magic attacks, as well as the extremely powerful moves Giga Flare and Ultima Blow. It can also heal with the Raise spell.
The Sage returns as a nu mou job. It still possesses the powerful Giga Flare and Ultima Blow attacks, but no longer can use Raise to revive party members, and Drain now belongs to the Arcanist. However, they have gained Scathe and are the only class able to use Esunaga. Oddly, they now have adequate stats in attack as well as defenses, though are still lacking in speed.
The Onion Knight retains his Sage EX Mode with the same effects.
Sage is also an advanced job that can be selected for a character in the player's Party for Quick Battle, Friend Cards, or wireless matches. Combining the powers of the Summoner, Black Mage and White Mage, and doubles the rate at which the EX Gauge fills.
Even these grandmasters of all magic are spent after casting their beloved Meteor spell.
The Sage is a character available to the party, he uses the Meteor ability during battle. Unlocks at level 56.
The Sage job appears with Thunder-, Fire-, Water-, and Ice-elemental cards.
Sage from Final Fantasy III has a Triple Triad card.