Okay... so we know that "source magic" (re: elemental magic) is a big part of the combat in Divinity: Original Sin, and we know what the reactivity of elemental spells will (or should) provide a great deal of depth to the combat systems.
But at this point, we don't really know much about just how reactive the magic systems will be aside from a few (very intriguing) examples.
For example, we know you can create puddles with a rain spell, which can then be frozen with an ice spell (creating a barrier to movement) or electrified with a lightning spell (creating a trap field).
But what other kinds of source magic reactivity might be cool to see in the game? Let's speculate!
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(O) If a fireball (or other fire spell) impacts over water (or if a rain spell is used on fiery ground), it creates a layer of steam over the water area, which decreases the accuracy of any ranged attack going through it, as well as any melee attack where either of the units involved is inside the steam. Steam would only last 1-2 turns.
(O) I think this is actually already in the current, pre-alpha build of the game, but if it isn't... characters who are wet should receive less damage from fire spells, more damage from lightning spells.
(O) Ice wall spells should be (significantly) stronger if cast over water.
(O) Same-element spells should be able to double up... I.E. if you've set a portion of the ground on fire with that one spell, and then toss a fireball on top of the burning ground... the fireball should either deal additional damage, or have a larger explosive radius.
(O) This may be a bad idea... but how about "dual" casting? Single spells (think "ultimate spells") with complementary elemental attributes? Like, for example, you couldn't do a spell of fire and water, because those two elements are opposed... but what about water and lightning? (I.E. a thunderstorm w/ random lightning strikes that deal damage and/or stun random units). Or mix water and ice to make a hail spell (random damage + decreased accuracy) or a snowfall spell (which would decrease accuracy--low visibility--as well as movement).
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Well, those are the ideas I have at the moment. I'm not entirely certain how the different elements will play off each other, but I think there's a lot of potential in the system Larian has created here. What kind of magic reactivity are you all expecting to see, or hoping to see?
