There are two main character types that rely heavily on what might be categorized as “civilized culture.” These tend to be priests (who tend to have an organized religious body to support them and cultivate their skills) and wizards (who need to have access to vast amounts of written material and laboratories to hone their skills). Of these two priests are almost always viewed as necessary to their societies and central to their communities. Wizards, on the other hand, tend to border on behavior more closely associated with hermits or quiet loners that up until the fireball incident displayed no danger to the neighborhood. But both require a goodly amount of book learning.
Most wizards would fall into the category of being mages, which is to say that they do not specialize in any particular school of magic. They therefore have access to all of the schools of magic and while they haven’t the ability to master any particular area of magical study they aren’t forbidden from any of the schools either. Mages can come from most any background and may have formal educations in magical skills or else have been apprenticed to the creepy bearded nut-job that lives in the tower out past Fenklerburn Manor. Game Masters must collaborate with the players in developing what exactly their mage is all about and how they came to even be mages because few people are able to master magic in the way that a wizard can. Think of them as Jedi or Sith. Not everyone has the gift.
Among those that specialize in a school of magic there are different titles bestowed. These individuals are given far greater access to those schools that they commit to, but as a counterbalance they are forbidden access to spells from what might be called “opposition schools.” Note also that according to the rules for AD&D 2nd Edition only humans can be specialists in most schools of magic. This is to prevent longer-lived races from horning in and just dominating as ultra-powerful sorcerers and to give players a better reason to choose to be human. Also note that the rules don’t apply if the Game Master says they don’t apply (and players are not Game Masters, so verify before writing anything down in ink).
The one school of magic that has the most cultural and societal restrictions is necromancy. This is for an obvious reason: people hate being hassled by ghouls. In most realms in Partum necromancy is strictly forbidden and specialists in this school will be difficult to locate under normal conditions. There is a well-known necromancer named Yeitic Morte that has set up shop in Mort-Vivant but he doesn’t travel around much because as a necromancer he is persona non grata in most neighboring countries. There are rumors of a young necromancer who is making a name for herself in Maelonbourg, but they haven’t really gotten any laws sorted out there for anything so that is to be expected. New players wishing to begin in Partum and wanting to play a necromancer need to be extraordinarily careful about how they go about setting up their backstory, position in whatever community they are in, and how they are going to keep themselves from going straight into evil mode.
Because this is one thing that is never going to be encouraged in this campaign. If you want to be evil stick to your Twilight fanfiction writing. We don’t do that here. Intentionally, anyway.