Hi, as you know we gonna implant Magic. So there are just some basic themes how magic could work.

1. Hell & Heaven
So there is Hell & Heaven, we are between those two worlds. Only Heaven & Hell have the power of Mana. So a Magican is actually steal the Mana out of one or both worlds too cast a spell. So it does matter which kind of Mana a Magican is using, when he is using more Hell-Mana, he gonna perform a spell like "Fireball", Hell spells are made too destroy. When he is using Heaven-Mana, he will probably cast something like "Lifewalk". A Teleport spell is based on both Mana, Hell & Heaven. A Magican need too use ALWAYS both energy, even Lifewalk need Hell energy, of course its not much of hell energy but you need it. Using Pure Mana will failing fatalaty. Using pure Hell Mana will burn the magican down, call a demon or creates a blackhole of death with endless pain. Using pure Heaven energy is so clean, that the magican is going too blind first and dies later, get frozen or turns into a spirit that walks on earth alone, he cant be seen, hearen and touched.
There could be Legends that survived casts like that, even more. Its gonna be sayd that they summoned Angels & Demons. But these are only Legends....

2. The Elementary Magic
We gonna add followed Elements: Ice/Water, Fire, Earth, Wind. Different Universitys teach different Elements. So i think its gonna explain it by itself. Casting a spell always required one of those Elements nearby. You cant control fire when there is no. Sure, there are Legends that have been talked about that they summon water in the middle of a desert or creates a whole island in the middle of a ocean, but thats are only legends....

3. The 12 Gods
This is my favorit one, but even still most complicated.
There are 12 Gods, for every month 1. And even a 13. God that known as the nameless god (BAD!).
All 12 Gods represents something.
Example: 1.Praios: Law & Order, 2.Phex: Luck, Play, Trading & Secrets (thiefs ), 3.Rhaja: Relaxing & Party, 4.Ingerimm: Smithing & Building, 5.Hesinde: Intelligence, Math & magic. 6.Travia: Farming & living at home sweet home. 7.Kor: Fighting for Money. 8.Rondra: Fighting for Honor. 9.Boron: Sleep & Death 10.Efferd: Ocean & Shipping 11.Tsa: Born & Peace. 12.Firun: Hunting.
There are even more Gods like Sturaria, for witches.
So beliving in one of the Gods is giving you powers that not beliver dont have. But you have too belive in this god and for no other. You respect the other gods, but you think your one is the best.
But all 12 god belivers thinks the same, the 13. god isnt good. He should never be named and any beliver of this god should get killed. Because the 13. god brings pain & sickness into the world, rats and plagues of insects and Murderer.

So thats my ideas of magic, choose one or post another idea