Wow, hats off to you guys for making such interesting and detailed magic system. Brilliant!
In my series, there are only four races that are able to wield magic: merfolks, fairies, witches and jinns. Every other race may have superhuman abilities, but they can't do what these four races are capable of.
Merfolks have the most limited form of magic, such as enchantment, teleportation, water bending and weather control. Only people who inherit merfolk blood can have their magical power.
Fairies are naturally the most powerful magical beings. They simply just need to will something to happen for it to happen. However, their magic is about depth. So if they don't train enough or they're not confident enough (yeah, fairies need to believe in themselves too), then their magic won't work. There's also the trouble with the fairy law that prevents them from doing whatever the hell they want to do. And just like merfolks, fairy magic cannot be learned.
Witches and warlocks' magic is all about knowledge and power. The more spells you know, more charms you have and more training you do, the more powerful you can be. Someone can be a witch or a warlock through lineage or learning. So you're automatically a witch or a warlock if you learn their arts. As a creation of fairies, witches and warlocks can use their magic to kill. Their creations, such as vampires and some species of werecats, are also free to take lives.
I didn't get to delve into the jinns in the series because it doesn't have much to do with the story, but they're part of the ancient race alongside with fairfolks and merfolks. In this world, most of the jinns prefer to live in their own realm, separate from humans. Biologically speaking, jinn is classified as family. Their species include ghouls and incubi & succubi who can enroll in Erebus and predominantly live among us, although they don't possess magical power. The jinns that possess magical power are the ones that grant wishes and send curses. Jinns, except incubi and succubi, can only procreate with fellow jinns, so only they can have this type of magic. They have so many strict rules. One of the traditional rules is that jinns and their creations, such as shapeshifters, cannot kill humans.
Aaaand... that's all, folks 