In Final Fantasy, there were most of the players thought that the Red Mage was overpowered by reason that the Red Mage had the ability to do everything just as efficiently as many other jobs in certain situations. You were able to say that a Red Mage is almost like Kakashi the Copy Ninja from the Naruto Series since he can also do just about every technique that others can do. What many people do not realize is that it takes much more effort for a Red Mage to imitate a different job because they do not have the job abilities that the other jobs may have on Final Fantasy XI.
Let us take this as example. A Red Mage can super tank like a Paladin in Final Fantasy XI but they won't have as much as defense as a Paladin. They will have Phalanx and Cocoon but they won't have Sentinel or Invincible in case things go terribly wrong. A Paladin can use Chivalry to restore their MP. A Red Mage would have to risk their life using Convert to restore their MP while they are super tanking. While a Red Mage would have the ability to super tank they would be not as good at it as a Paladin. The same goes for a Red Mage tanking in a regular experience party. They can tank with a shield but they would have a hard time getting the enmity they need so the enemy can attack them instead of their allies.
   And also there are lots of people have noted another thing about the Red Mage is its fast cast trait, which allows a Red Mage to sub Ninja and effectively Ninjitsu for shadows to absorb the damage and as well it shortens the casting time of their spells and aids in both party and solo play. In an emergency situation you can use your two-hour ability Chainspell to instantly cast spells for 30 seconds. While wearing the Warlock Chapeau and the Duelist Tabard, a Red Mage can cast Ichi spells almost as fast as a Ninja can cast Ni Spells, which means that a Red Mage would never have any problem putting up their shadows to block all of the damage. Since they have the ability to cast Haste, they will also see that the recast time for casting spells has almost been cut in half. That allows a Red Mage to constantly be able to throw up as much shadows as Naruto can when he does his Mass Shadow Clone technique. In a game like Final Fantasy XI, being able to do that will allow you to fight even the toughest of Notorious Monsters.
   The Red Mage will have a good chance of beating Notorious Monsters if there is a Notorious Monsters can not break through shadows fast enough. Even if they break through a Red Mage will always have the ability to use Phalanx and Stone skin.
   Through the above-mention discussion, we hope that you can familiar with this information that a Red Mage can solo so many Notorious Monsters. Best of luck!