I have completely learned how to decimate Dusks and Assassins, because like you said, very repetative AI pattern... It's actually kind of... annoying, now. I've been circling Twilight Town for... well, a long time now, and before that, the whole Awakening thing. It's a goal of mine to get Roxas to RIDICULOUSLY high levels before trading off to Sora. I'm insane, or something, I guess, 'cause he's in the 20's now. ...But I'm kinda bragging, here. The point is that they didn't put too much effort in giving enemies individuality. Every time I see an Assasin, I wait for about a half-second, use Guard, it's stunned, I smack it about 3 times and it dies. No damage on me. Dusks are oddly more versitile, though. I think it's because of that one first attack that Assassin's do, whereas they sometimes fan out and double back.