Phantom offers three unique Spells, each of which can be highly effective in the right situation. Vanish gives the target the ClearStatus, as does the Fader summon. Bserk can pump up the damage of melee attackers or shut down enemy spellcasters. Demi halves an enemy's HP, but is resisted by a large number of Monsters.
Phantom is also noteworthy as the first Esper that offers a Level up bonus to MP.