[@KatherinWinter]
I have just posted something that has Canon elements.
That includes affinities. That explains why Gray learned Demon Slaying magic despite having Ice create magic. 
Lol spoiler. 

Ahh... Sorry to those that is reading or watching Fairy Tail. My current post contains spoilers.

Though it is mostly concerns in Terrounjima arc, Post-zero arc and zero arc 
But don't worry, I just gave hints....