Ultima Charge is learned by the Mog Knight. It costs 60 MP to cast, as do the other variants of Ultima.
The Moogle Knight learns this spell. Ultima Charge is magic-oriented, so high magick makes this attack more potent. It costs 32 MP, so without an external source of MP it will take four turns before a moogle can use it. With MP Efficiency or MP Channeling, this attack can be used every other turn. Paired with a Cannoneer and its Ether Shell ability, the moogle can use this attack just about every turn.
Ultima means "the last" in Latin and many Latin-based languages. In the Spanish versions of many Final Fantasy games, it is written as "Artema," a close transliteration of the Japanese katakana.