Logan of course, but the females really came to the party in this one, Yukio, Mariko and Jean were superb, only Viper was a bit of a meh to me. Shingen was also great, a nasty piece of work, but that fight with Logan was just too good.
I liked old man Yashida as well, I like how it portrays at the start that he and Logan were friends when they met, but really he was obsessed with his ability to survive and wanted it for himself, a decent motivation for the character.
Harada was pretty much pointless and the weakest link, biggest dissapointment to me.
Honourable mention to the guy in the red pants also