Isn’t the shadow counter frame data roughly the same as when you do the shadow move normally?
Yes. The shadow that comes out for a shadow counter generally has the exact same properties as it does raw. I think Aganos’ got some kind of interesting tweak though, as I’m pretty sure that it behaves slightly different than a normal shadow natural disaster. As far as I know, he’s the only character this applies to however.
I think that was the other guy with a tie, @Infilament, who said that, but I don’t know about any invulnerabilities on it. In fact, there’s a bug where it can get stuffed on frame 0 even if he has armor.
But it is the fastest in the game at 7 frames and it recaptures. The startups are listed in the KI bible:
http://ki.infil.net/meter2.html#scounters
Shadow counters kind of work oddly if you get into the nitty gritty of it. Everybody has the same pre-screen freeze activation, which catches a strike but then ALSO must undergo the exact same number of frames before the screen freeze is launched (I think it’s universally 5 frames). So… you press MP+MK, then you enter your parry state. If you catch a hit, you undergo 5 frames of totally not invincible startup (and, I guess in Aganos’s case, this startup doesn’t apply armor if LeoFerreis is accurate). When you hear the announcer yell “shadow counter!” but no freeze happened, this is why… you got hit in those 5 frames. Then the screen freeze happens and there is some amount of post-freeze startup as well, which is move dependent. And I think this post-freeze startup is the same as the neutral shadow move’s post-freeze startup, but don’t quote me on that.
Aganos’s is really weird. As far as I can tell, it is invincible post-freeze until the first active frame (I think bastfree did some frame-by-frame analysis of this and there was no hitbox at all). You can shadow counter Fulgore’s light laser and then blow through a pip-canceled DP with Aganos, something no other character can do. He can also shadow counter the 2nd hit of blocked Jago shadow wind kick and somehow avoid the 3rd hit, which would stuff any other shadow counter (and of course, he recaptures at the end). I’m preeeeetty sure this isn’t because Aganos’s SC is simply fast enough to go through wind kick, but rather because he’s invincible and shadow wind kick is juuust slow enough that he won’t get tagged in the 5f of vulnerability pre-freeze.
Aganos’s SC is by far the best in the game though. Shadow Jago’s comes in second at 8f, and then S1’s fastest SCs come in next (Wulf/Sadira at 9f). Jago’s is actually quite slow at 12f, but because it’s throw, low, and projectile invincible, sometimes it beats people who pressed a button when they could have blocked, whereas someone like Hisako’s SC (also 12f) won’t do that. Maya and ARIA have the worst SCs in the game (to the surprise of no one) at 17f startup. They’re so slow that you can’t even shadow counter some shadow moves on block, like Cinder shadow Trailblazer or Omen shadow Furious Flurry.