Well, most mages learn elemental magic, which is where you study lots and then you're able to manipulate fire, or lightning, or wind, or whatever. I mean, some people will never be able to cast a spell ever, but most people with any magical competence can manage elemental with the right training.

But me, I'm a dark mage! Dark magic is kind of different because you really have to be born with an aptitude for it, and it doesn't rely on earthly stuff like elements. It's more like... if elemental controls the stuff you can see, dark controls the stuff you can't! Like illusions, mind control, dreams, insta-death, stuff like that. But it also takes way more effort to set up and cast.