Basic rule of thumb is if it'd take me more than an hour to code, it's too complicated to be an edge.

Also, I'm not really sure how this would roll with the affinity system. Would you need to have both high fire affinity and high ice affinity to change a fireball to cold damage? I can't see how anything but a 'yes' answer to that question would be balanced. At which point... why not just cast an ice spell?

Make it such that invoker edges allow invokers with paths of affinity 8 or higher to shatter the shields of opposing invokers causing terrific damage to the bearer of that shield. That's a long sentence, so an example...

An invoker with 8 affinity in fire (heretofore called firevoker) fighting a warrior wearing the shield of an invoker with a lower affinity in water, ice, etc.

The firevoker casts a controlled fireball at the warrior (echoes will be incorrect)

Firevoker's controlled fireball evaporates your watershield!
Your scalding steam ===ANNIHILATES=== you!
Firevoker's controlled fireball shatters your iceshield!
Your shards of splintered ice ===ANNIHILATES=== you!
Firevoker's controlled fireball boils your oozeshield!
Your boiling grease peels flesh from bone!
Your boiling grease does UNSPEAKABLE damage to you!

Essentially it's dispel magic with damage.

Dragon breath blasts shatter shields. Get one of the 'blasting' items in game for that.

Edit: Also, its not about 'power gaming'. Edges/affinity were never about making your fireball do a neat row of annihilates - they were about making it smarter in some situations than others (where pure damage is sacrificed for malediction/utility). With this system, you could knock out a warrior, shield him up with shields you can shatter, then just fireball twice and he's dead.

Yhorian.

But invokers can already throw spells of different elements. This kind of stuff is done with affinities, so the suggestion is kind of moot. As for opposite pairings, earth-air, fire-water, ooze-smoke, magma-ice. As for lightning, dunno, maybe salt. I'd imagine lightning to be above or below the plane of smoke(helpfiles state that quasi-elements are above and below elements or para-elements. It is somewhat unclear comparing the helpfile and what is said on the page).

As related question, where exactly do the quasi-elements lie? Has it been officially defined?