I have been thinking a little regarding illusion magic after reading most of Ghost Story. Without spoiling anything in the book, there is a wizard who, in combat, casts a spell that creates a handful of copies of the wizard with the intention to confuse the attackers (the copies fights with “guns” but cannot affect the opponents, so they tend to “miss” a lot). How would you do this in the game?
First off, the copies are neither real nor physical, so we are not talking about conjuration. The first idea is that it is made a kind of veil affecting an entire zone (assuming that the five copies are in the same zone). One can veil an entire zone using an Evocation Block (+2 Complexity for an entire zone). What I am against using the route is that it would in that case be possible to create any number of copies in that zone for a mere +2 Complexity. A note – the copies move around and “act” individually, it is not one big “thing” (that a zone-wide veil can be seen as).
If it is modeled as Thaumaturgy, one could go this route: Use a base complexity of whatever the difficulty would be to visually see through the illusion (basic strategy for any veil). Add +2 for extra sense that is affected (in this case, sound is definite added). Add +2 for each extra copy (i.e. +2 for a total of 2 illusions, +4 for three illusions etc). For five Superb copies of the wizard using sight and sound, the Complexity would be 15. Really, really, hard to do using Evocation, but not impossible using Thaumaturgy.
How would you do such a spell in the game?