Katara... Honestly, Zetta has no idea why he likes hangs out with uh, does whatever it is in the depths of his twisted demonic mind he's doing with Katara. He thought that whole ice thing she did was pretty cool. And she understands enough not to call him on the fact that he's not really that bad a guy not talk up love and friendship a lot. Really, though... he doesn't know why he feels protective of her, and in classic Zetta fashion he solves the problem by ignoring it.