Avoidance Kata is kind of an odd duck. (*cough*) Note that it doesn't actually change the past—-fate doesn't do that. What Avoidance Kata is is a message to the Loom of Fate in the *now* saying, "Oh, by the way, I foresaw this, and I'm not here."
And it's true.
As far as anyone can prove. (See "On Memory", p. 131.)
The demon, if high enough rank to be outside of fate, will remember the first few seconds of the fight. It will be aware- if intelligent enough to grasp the idea- that the Sidereal decided retroactively that she was never there.
Others watching the fight will remember the first few seconds, but, well, obviously they were confused, since it's transparently clear that the Sidereal was never there.
For most practical purposes, she wasn't!
People remembering her there is the controlled equivalent of the glitches in fate you get when the loom snarls—-you know, the ones where people drown after being pulled out of the lake, or get hacked into pieces and wake up the next morning perfectly fine.
If it's the one I'm thinking of, you're reading too much into it.
Sidereals can get away with things like Avoidance Kata because reality *is* the Loom of Fate. If the pattern spiders decide that the Sidereal was somewhere else all along, it means that that's the new context for events.
("Hi! I just appeared. I've been here all along."
"Yah. I noticed."
It doesn't actually mean that the past changed, or that it fits all the facts. In fact, cleaning up the snarls that *anyone's* Charms can lead to -such as people drowning in a lake and then going back to their life rather than reincarnating- is part of the Sidereal job.
I theorize that this is, in part, why Sidereal Charms don't get Paradox. A certain amount of screw-up is necessary when you try to apply fate to high-Essence types, and the spiders are happier when at least it's one of a limited group of roughly 150 effects than when it's 'anything at all' like with astrology. Sidereal Charms, because of the direct fate manipulation, are more blatant about this than Solar Charms—-but even so, every time you use Excellent Strike or, heck, a stunt, there's a small but meaningful chance you're screwing up fate's plan for you.
Some people have accurately spotted the intended logic behind this—-that it's easiest to pin down a Sidereal who thinks she's going to win.
But it's true; not every character has the kind of mind that works that out. Luring the Sidereal into committing herself is an obvious trick—*if* you know that Avoidance Kata *can* be beaten. And some Solars will start with the assumption that it can, because assuming unbeatable opponents is pointless; and other Solars will get frustrated and go pound a city to ruin to work off their tension; and others yet will go off on blind-alleys like investigating what messes with prophecy.
However, the other suggestion floated on this thread- give the Sidereal something to fight for- is solid. One of the major ways that Avoidance Kata isn't as good as *actually* not being there is … you don't get to retroactively implement a backup plan. Your Storyteller can, if she chooses, but the Sidereal's player doesn't get to. And that means that declaring "I'm not here!" when your family or your stuff or everything you've worked your life to build is being threatened …
… isn't something you're going to do unless you're *totally* sure you can't win.
It's up to the Storyteller.
I recommend erasing mundane evidence and things done by or to the Sidereal on the turn the Charm is invoked.
SIDEREAL: I get initiative. I throw some knives and enhance them with a Charm.
ABYSSAL: I cut off the Sidereal's arm.
ABYSSAL: I get initiative and cut off the Sidereal's other arm.
SIDEREAL: Er. Suckweasel. Um.
SIDEREAL: I'm not here.
The ABYSSAL: hurt by some knives. Who hurt him? He's not sure. Maybe he just burst into cuts. That happens sometimes.
The SIDEREAL: in the woods somewhere, looking blankly at a bear that has just torn off her arm. But at least she still has *one*.
SIDEREAL: Why am I fighting a bear?
STORYTELLER: For my amusement.
STORYTELLER: You're trying to demonstrate your l33t sk1llz to that wind spirit you've been flirting with. So far, it's not going very well.
THE KNIVES: Back on the Sidereal's belt.
And, yes, the Siddy's going to beat the bear. Having to repeat Avoidance Kata several times is just silly. :)
My copy of Lunars isn't handy, so I can't check text. Thus, I can't give a ruling.
In *general*, I don't see why something like that wouldn't work. The Sidereal isn't "wasn't ever there" *yet*. If you keep the Sidereal from becoming "wasn't ever there" while the Sidereal is still "was already there", the Sidereal won't never have been there to begin with. That's logic.
So I'd definitely allow it in a Lunars game, or a Sidereal game (although Storytellers should use it with caution). I would need to analyze text to see whether it'd be appropriate in Exalted: Kombat or an Exalted MUSH. I don't know of any of the latter, though, and if you're using Avoidance Kata in an E:K duel you have something wrong with your brain, so :)
It may help not to think of it as deception or mind control. It's information.
When you say "You suddenly realize that the Sidereal was never here," you're not lying to the PCs and asking them to swallow that lie. You're giving them data. It's not data they completely understand, it's just an instinct, but that happens a lot with weird supernatural effects—-you realize something, but not necessarily the whole picture.
In this case, you're telling them "the Sidereal was never here" because that's how people in the world sense, process, and understand "the Loom of Fate has just updated to declare that the Sidereal was never here."
It's like telling them "that didn't happen" to explain a sorcerous illusion, when they roll well enough to figure out that something funky went on but not well enough to figure out what. It's not trying to fool the PCs. It's trying to give them data.