The first rule to be unveiled, and is being seen in action in the Grean campaign, is the inability for spells of different schools to interact. The breaking of the circle destroyed the ability of spell to work at the same time on specific targets. That which weaves spells together is gone.
What this means in game terms is that no target can have multiple spells from different schools acting on it at the same time. So you could have Haste and Enlarge (both transmutation), but you could not have Invisibility and Haste. If it occurs that a target has one spell on it and then another one is subsequently cast on it, the target may decide which spell(s) continue. If the target is no capable of deciding, the more powerful spell(s) win. Power for this is total spell levels of the school. Ties go to the one that was there first.
Note that any item possessed by a target is part of that target for this purpose. You can't cast one spell of each school of eight different items you are carrying. Also note that this does not apply to magic item effects unless the effect is from an item that cast a spell. So boots that always allow you to fly are fine, but a wand that casts fly on you is not.
Also note that there are two tracks for spells cast on a target that do not interact, helpful and harmful. These types of spells are not working together and hence interact in different ways. So you could have an Invisibility spell (helpful) and a Slow spell (harmful) at the same time. A target does not get to choose which harmful spell is active on it.
These rules only apply to spells with duration. Spells with a duration of Instantaneous or Permanent act normally. An example of this was used this past week with Love's Lament.
Comments, thoughts, questions?
