[quote=@Pie Flavor]
I have a question, If a Black Mage was to specialize in using diseases as their primary use of magic. Would they also be able to heal people of diseases as well, by manipulating it to slow down or stop it entirely and if possible then reverse it? Honestly a White mage would simply be a better doctor but i would like to see how a black mage would do as a doctor.
[/quote]

I love it when people ask good questions. :D

A Black Mage would only be privy to their own disease. If they poisoned someone they would be able to halt and heal the poisoning. As well, if it was a natural disease and the Black Mage was able to recreate that disease already they could reverse it. An unfamiliar disease or one placed by a different Black Mage would be impossible to do, unless your Black Mage learned all about the new disease right quick. In situations like that a White Mage holds up better because their magic is more adaptive to illnesses.

A Black Mage doctor is entirely within the realm of possibility, though most Black Mages that are also "doctors" are also probably mad scientists and the like.