Fuck yes, Kariya. I think next episode they're going give him some screentime - He was talking in the preview, and Rin's in it as well.
I like Kariya because he became this horrible, misshapen monster to save the world he loved, even at the cost of his own life. Of course, it ends up being really, really sad because the audience has to have at least a vague inkling of an idea as to how his story will end...
Him and Kiritsugu are probably my two favorite Masters. Kiritsugu's just so damn slick about everything he does.
Favorite Servant has no contest, though. No contest.