Kratos, Spawn, Heihachi, and Link have all been in it. They were actually going for Cloud, Sepiroth, and 2 other Characters, but since Dissidia is out, they do not think they would be able to get them. Ezio looks like he will fit well in this personally. He had a Comical character who fought with his Weapons before in the same game as Kratos.
[video=youtube;0jBz4hEoj5k]http://www.youtube.com/watch?v=0jBz4hEoj5k[/video]
Now remember this. The video posted above is a fighting game with mostly broken characters. Though the fighting style in Soul Caliber 5 will be faster then any other Soul Caliber yet.
[video=youtube;ePpaPUXfiN8]http://www.youtube.com/watch?v=ePpaPUXfiN8[/video]