It came out a couple years ago, and was either on Nick (most likely) or Cartoon Network. It was, I believe, an American take on anime-style that took place in a semi-post apocalyptic world. I never got to see enough episodes to get the entire premise, but the show focused on a brother and sister who live in a world that is floating in the sky. There is some evil villain who always seems to be after the sister because she has powers and he thinks she has the answer to some big secret. The siblings learn to hate this guy because he took their mother away from them (although they don't know this at the beginning). I think the sister's name is something like Lianna, or Li... something, but don't know for sure. The series only lasted a little while, and I don't know if it even got to finish the first season.

I think the title contains all or some of the following words: sky or world.


Thanks to anyone who can help!

Was it CG

Try,.

Skyland

floating worlds seem to be a reoccurring environment
in French cartoons. Skyland, Dragon Hunters,Code Lyoko,
Dragon Flyz