On the design document, there are indications that magic will be governed by mana, and there were at one point magic classes designed around which elemental plane they used magic from.
I was wondering what details of the magic system have been settled on, and the overall scope of it. Are there going to be specific spells that you can learn? Would you learn new ones from leveling, or by finding them in the world?
I can see lots of ways to handle it that could be cool. If magic spells could be found as loot, it also opens up them being learned from teachers, so you could find a wizard to teach you in exchange for services. Particularly powerful spells could be another form of artifact-level loot.
Scrying spells would also be cool to see. I could see spells that let you view obstructed areas as if you were standing there, or spells which give you peeks into the AI's thought processes, or a spell to let you communicate with a creature at long range.
Summoning could be interesting if the summoned monsters don't like you, and will try to work against you within the bounds set by the spell. Summoning demons is a classic example, in many fantasy stories it is very dangerous because if any of your protection spells fail, the demon will do horrible things to you. This could also allow you to summon a demon to question it, as they might be particularly knowledgeable.
This leads to the possibility of ritual magic, where the success is dependent on performing a series of steps in the gameworld, like putting objects in certain configurations or saying certain incantations.