[quote=@Zeroth]
Will magic take the form of general manipulation of the element(though darkness seems to include summoning), or do we need to come up with specific abilities that would be somewhat unique to our characters using those mediums? And if it's the latter, do we need to run those special abilities past the GM/co-GM?
[/quote]

For the most part, it's general element manipulation. However, usage of magic has drawbacks and different magic has different consequences. For example, using shadow magic does not allow you to summon things; rather, the drawback is that it lowers your character's sanity and they'll soon start to see things that shouldn't be there. But yes, you are allowed to be more creative in your usages of magic. Provided you run those creative juices with the GMs first.