User blog comment:LaviBookman/Magic Discussion/@comment-1399043-20120620072510/@comment-4509522-20120620201620

They can only control one specific magic type. For instance, a user who has an affinity for fire cannot use water or other elements. However, magic types can be enhanced to where they perform basic functions. This one is kind of cliche, but just for an example, a person who controls fire can also control smoke or steam.

Weapons in this universe can be merged with magic to be more effective and powerful. In a broad sense, I compare it to Fullbring (which stole my idea -3- jkjkjk). Having a specific item such as a sword, and then merging it with your fire powers makes it a more powerful sword that can manipulate fire as well.

I know those are all simple examples, but you get the idea. Does that answer your question? :3