[quote=@RoadkilBanana]
Would someone please explain to me magic stuff? I was planning on using a kind of healing magic, but I don't know if I can make my own spells or not...
[/quote]
Yes, you can make your own spells. If you read Zeroth's response to Sylvan on the previous page*, you can see that healing is just a "type" of spell like reinforcement. For example among the accepted characters, off the top of my head Illios and Parin can both heal and they have sun magic and water magic respectively. Generally you will want to pick a "theme" for the magic first, and work on spells from there. You can watch or read the first part of the anime where they explain it, or cruise the wiki, or browse the character tab to see how everyone else did it. 

Edit: make that page 12, since my reply made a new page...