you can either learn one or the other, but cannot learn both. Spirit Arts, as it's called, are harder to learn than the stereotypical "magic", and fewer people have an affinity for it, so most people default to learning magic. Rio, however, learned Spirit Arts (the woman in C3 helped him learn it), and thus, he couldn't learn magic, which he got mocked for at the academy. As for the woman's identity......that's information for later.