If you want to rp multiple classes, go ahead, that's cool, in fact that is what I do, Nako is a teacher of Aether for the three major styles (Thaumaturgy, Conjury and Arcanima(sp?)). he has done lectures at the different guilds before. however, he does not have any practical knowledge of the more advanced methods, (summoning, black magic, succor, scholary goodness) all he has is theoretical knowledge.
however, I would stray away from being a practicioner of multiple job styles of Magic, they are supposed to be rare in and of themselves, and for one person to be a master of multiple Jobs I would find it hard to believe without it being mary sueish.
as to the second bit, i don't believe it would be possible, I think any white mage caught by the elementals playing around with black magic would find themselves stripped of their ability to use succor.
this is only a quick answer and I will go into more detail when I am able.
however, I would stray away from being a practicioner of multiple job styles of Magic, they are supposed to be rare in and of themselves, and for one person to be a master of multiple Jobs I would find it hard to believe without it being mary sueish.
as to the second bit, i don't believe it would be possible, I think any white mage caught by the elementals playing around with black magic would find themselves stripped of their ability to use succor.
this is only a quick answer and I will go into more detail when I am able.
Aduu Avagnar, The Wanderer: Wiki