In Teen Titans #39, we meet Zantara and Miss Martian–2 more members from the Titans of “last year”.
Zantara is just a brat. It is plain and simple.  He thinks he is something special and the Teen Titans owe him something. I’m not sure why is is all mad at the rest of the group, but it easy to see why he is hard to get along with.
Looking at my comic book archives, I see that Zantara is not new, but it seems that DC has revamped him for the new series.