The FFXI Red Mage is a character class that delves in the art of Black and White magic. This may seem a unbalanced class, especially once you consider that he can fight with weapons much better than Specialty Mages.Their wide variety of skills, though, also means that they are not a master of anything with the exception of Enfeebling. They can neither remove all status ailments or heal as proficiently in high levels as well as a White Mage. They cannot do nearly as much damage as a black mage with offensive magic having no access to Ancient Magic or higher tier Black Magic spells. In combat, they are not as deadly as blue mages with a sword or as handy as a thief with a dagger.
The role of red mages in parties has evolved through the course of FFXI. Early on, the primary responsibilities of red mages including enfeebling, crowd control (keeping links slept), nuking, backup healing and meleeing. However, the red mage's role changed drastically with the release of the Treasures of Aht Urhgan expansion. The expansion introduced several high-level mobs to the game with low defense and low hit points, ushering in the "TP burn" era of FFXI. In these style parties -- in which melee jobs zerg the monsters, killing them quickly -- the responsibilities of the red mage were virtually narrowed to curing and hasting. Mobs in ToAU areas generally don't live long enough to warrant enfeebling or nuking, and bards often take care of crowd control issues.
A player can begin the game as a Red Mage. If he chooses to do so, he will be given an onion dagger as well as a scroll of their first Enfeebling Spell Dia in addition to his normal racial starting gear. You can choose to become a red mage very easily.